13th PSI Summer SchoolZug August 9-15 2014 1Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC CLOCKS BASIC PRINCIPLES APPLICATIONS AND CURRENT TRENDS

Gaetano Mileti Laboratoire Temps ndash Freacutequence (LTF) Universiteacute de Neuchacirctel

13th PSI Summer SchoolZug August 9-15 2014 2Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LABORATOIRE TEMPS ndash FREacuteQUENCE (LTF)

Time amp Frequency metrologyAtomic spectroscopyPrimary standardsOptical clocksCell standardsSpace clocks

Optical metrologyOptical combsXUV frequency combsStabilized lasersLaser characterisationLaser instruments

13th PSI Summer SchoolZug August 9-15 2014 3Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 4Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RECENT NOBEL PRIZES IN PHYSICS RELATED TO THE FIELD

2012 S Haroche D Wineland

Control of individual quantum objects Photons and atoms

2005 J Hall T Haensch R Glauber

Laser precision spectroscopy Optical comb Quantum optic

1997 S Chu C Cohen-Tannoudji W Philips

Laser manipulation of atoms

1989 N Ramsey W Paul H Dehmelt

Separated oscillatory fields method for atomic clocks

Ion trap techniques

And several others in the previous years (Kastler optical pumping etc)

13th PSI Summer SchoolZug August 9-15 2014 5Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 6Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Definition in SI system

The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of cesium 133 (1967)

Hzh

EEFrequency 7706311929120

AtomsQuartz oscillator

Reference for the user (5 MHz)

Interrogation

Feed-back

F=4

F=36 Sfrac12

This would be the frequency of an atomic clock in which the atomic transition is not perturbed and the stabilisation ldquoperfectrdquo

ATOMIC CLOCK FREQUENCY-STABILIZED OSCILLATOR

00

1

TPeriod

13th PSI Summer SchoolZug August 9-15 2014 7Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY DO WE NEED TO STABILIZE THE QUARTZ

Slide from JohnVig tutorial on laquoQuartz crystalresonators and oscillatorsraquo

13th PSI Summer SchoolZug August 9-15 2014 8Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FIRST OVERVIEW OF APPLICATIONS AND NEEDS

Agriculture (seasons) ~ 1rsquo000rsquo000 s

Calendar (solstices equinoxes) ~ 100 rsquo000 s

Daily activities (professional social etc) ~ 1rsquo000 s

Determination of the longitude (sea navigation) ~ 1 s

Common electronic and telecommunication devices ~ 001 s

Advanced telecommunication devices ~ 0000rsquo001 s

Satellite navigation ~ 0000rsquo000rsquo001 s

Scientific research and primary metrology lt 0000rsquo000rsquo000rsquo1 s

Need of atomic clocks (in the device or to calibrate the device)

10-11

10-14

lt 10-14

13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Typically 5 or 10 MHz

9 192 631 770 Hz

Magnetic resonance

BLOC DIAGRAM OF AN ATOMIC CLOCK

Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator

bull Statistical and non-statistical analysis

Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo

Systematic bias

Frequency of the oscillator

Statistical fluctuations

STABILITY AND ACCURACY

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

0

13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ALLAN DEVIATION

Frequency of the oscillator

1 )(1 K

K

t

tK dttyy generalindivergesyvarianceTrue ky22

212

12 )()( kky yy deviationAllany )(

bull Different types of noise processes affect differently the Allan deviation

bull Different applications require different (in)stabilities at given time scales

y() tells us how the

oscillator under test compares to an ideal one

over the timescale

13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Magnetic resonance allows ldquospin fliprdquo

Magnetic resonance is a frequency selective phenomenon

Sig

nal

Probing frequency

Linewidth 0

0

0

Q

21

)(20

NSQ

Iy

BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE

J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981

Allan deviation

0

RT1

0

R resonance laquodurationraquo

13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Discriminatorslope D

Detection noise

Frequency noise

The most important parameters for the clockperformances are

The resonancequality factor Q

The signal to noise ratio SN

RELEVANT PARAMETERS OF THE RESONANCE SIGNAL

13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

BLOCH VECTOR FORMALISM (SEMI-CLASSIC)

2E

1E

The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field

Microwave transitions optical transitions 2 pulses etc

Atom (or ensemble of atoms)

Interacting field (RF microwave optical)

Bloch vector (fictitious spin)

tie

12 EE

spopulationofdifferencequadratureindipoleatomic

phaseindipoleatomic

wvu

s

R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)

13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHAT HAPPENS IN AN ATOMIC CLOCK

Generalised magnetic resonance allows ldquospin flipsrdquo

It is a frequency selective phenomenon

In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator

In each type of clock it is realised on different species in various configurations and with different detection techniques

Sig

nal

Probing frequency

Linewidth

Or series of pulses such asThe Ramsey scheme (2)

13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS

- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations

- Put (or select) as many atoms as possible atoms in one(of the two) levels

- Perform the ldquomagnetic resonancerdquo (in one or more steps)

- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)

- Apply the necessary correction to the quartz oscillator

000

s

100

13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC BEAM FREQUENCY STANDARDS

Stern-Gerlach (State selection) and Ramsey interrogation

000

s

0)cos()sin(

0

0

tt

100

010

100

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 2Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LABORATOIRE TEMPS ndash FREacuteQUENCE (LTF)

Time amp Frequency metrologyAtomic spectroscopyPrimary standardsOptical clocksCell standardsSpace clocks

Optical metrologyOptical combsXUV frequency combsStabilized lasersLaser characterisationLaser instruments

13th PSI Summer SchoolZug August 9-15 2014 3Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 4Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RECENT NOBEL PRIZES IN PHYSICS RELATED TO THE FIELD

2012 S Haroche D Wineland

Control of individual quantum objects Photons and atoms

2005 J Hall T Haensch R Glauber

Laser precision spectroscopy Optical comb Quantum optic

1997 S Chu C Cohen-Tannoudji W Philips

Laser manipulation of atoms

1989 N Ramsey W Paul H Dehmelt

Separated oscillatory fields method for atomic clocks

Ion trap techniques

And several others in the previous years (Kastler optical pumping etc)

13th PSI Summer SchoolZug August 9-15 2014 5Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 6Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Definition in SI system

The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of cesium 133 (1967)

Hzh

EEFrequency 7706311929120

AtomsQuartz oscillator

Reference for the user (5 MHz)

Interrogation

Feed-back

F=4

F=36 Sfrac12

This would be the frequency of an atomic clock in which the atomic transition is not perturbed and the stabilisation ldquoperfectrdquo

ATOMIC CLOCK FREQUENCY-STABILIZED OSCILLATOR

00

1

TPeriod

13th PSI Summer SchoolZug August 9-15 2014 7Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY DO WE NEED TO STABILIZE THE QUARTZ

Slide from JohnVig tutorial on laquoQuartz crystalresonators and oscillatorsraquo

13th PSI Summer SchoolZug August 9-15 2014 8Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FIRST OVERVIEW OF APPLICATIONS AND NEEDS

Agriculture (seasons) ~ 1rsquo000rsquo000 s

Calendar (solstices equinoxes) ~ 100 rsquo000 s

Daily activities (professional social etc) ~ 1rsquo000 s

Determination of the longitude (sea navigation) ~ 1 s

Common electronic and telecommunication devices ~ 001 s

Advanced telecommunication devices ~ 0000rsquo001 s

Satellite navigation ~ 0000rsquo000rsquo001 s

Scientific research and primary metrology lt 0000rsquo000rsquo000rsquo1 s

Need of atomic clocks (in the device or to calibrate the device)

10-11

10-14

lt 10-14

13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Typically 5 or 10 MHz

9 192 631 770 Hz

Magnetic resonance

BLOC DIAGRAM OF AN ATOMIC CLOCK

Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator

bull Statistical and non-statistical analysis

Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo

Systematic bias

Frequency of the oscillator

Statistical fluctuations

STABILITY AND ACCURACY

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

0

13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ALLAN DEVIATION

Frequency of the oscillator

1 )(1 K

K

t

tK dttyy generalindivergesyvarianceTrue ky22

212

12 )()( kky yy deviationAllany )(

bull Different types of noise processes affect differently the Allan deviation

bull Different applications require different (in)stabilities at given time scales

y() tells us how the

oscillator under test compares to an ideal one

over the timescale

13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Magnetic resonance allows ldquospin fliprdquo

Magnetic resonance is a frequency selective phenomenon

Sig

nal

Probing frequency

Linewidth 0

0

0

Q

21

)(20

NSQ

Iy

BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE

J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981

Allan deviation

0

RT1

0

R resonance laquodurationraquo

13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Discriminatorslope D

Detection noise

Frequency noise

The most important parameters for the clockperformances are

The resonancequality factor Q

The signal to noise ratio SN

RELEVANT PARAMETERS OF THE RESONANCE SIGNAL

13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

BLOCH VECTOR FORMALISM (SEMI-CLASSIC)

2E

1E

The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field

Microwave transitions optical transitions 2 pulses etc

Atom (or ensemble of atoms)

Interacting field (RF microwave optical)

Bloch vector (fictitious spin)

tie

12 EE

spopulationofdifferencequadratureindipoleatomic

phaseindipoleatomic

wvu

s

R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)

13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHAT HAPPENS IN AN ATOMIC CLOCK

Generalised magnetic resonance allows ldquospin flipsrdquo

It is a frequency selective phenomenon

In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator

In each type of clock it is realised on different species in various configurations and with different detection techniques

Sig

nal

Probing frequency

Linewidth

Or series of pulses such asThe Ramsey scheme (2)

13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS

- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations

- Put (or select) as many atoms as possible atoms in one(of the two) levels

- Perform the ldquomagnetic resonancerdquo (in one or more steps)

- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)

- Apply the necessary correction to the quartz oscillator

000

s

100

13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC BEAM FREQUENCY STANDARDS

Stern-Gerlach (State selection) and Ramsey interrogation

000

s

0)cos()sin(

0

0

tt

100

010

100

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 3Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 4Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RECENT NOBEL PRIZES IN PHYSICS RELATED TO THE FIELD

2012 S Haroche D Wineland

Control of individual quantum objects Photons and atoms

2005 J Hall T Haensch R Glauber

Laser precision spectroscopy Optical comb Quantum optic

1997 S Chu C Cohen-Tannoudji W Philips

Laser manipulation of atoms

1989 N Ramsey W Paul H Dehmelt

Separated oscillatory fields method for atomic clocks

Ion trap techniques

And several others in the previous years (Kastler optical pumping etc)

13th PSI Summer SchoolZug August 9-15 2014 5Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 6Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Definition in SI system

The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of cesium 133 (1967)

Hzh

EEFrequency 7706311929120

AtomsQuartz oscillator

Reference for the user (5 MHz)

Interrogation

Feed-back

F=4

F=36 Sfrac12

This would be the frequency of an atomic clock in which the atomic transition is not perturbed and the stabilisation ldquoperfectrdquo

ATOMIC CLOCK FREQUENCY-STABILIZED OSCILLATOR

00

1

TPeriod

13th PSI Summer SchoolZug August 9-15 2014 7Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY DO WE NEED TO STABILIZE THE QUARTZ

Slide from JohnVig tutorial on laquoQuartz crystalresonators and oscillatorsraquo

13th PSI Summer SchoolZug August 9-15 2014 8Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FIRST OVERVIEW OF APPLICATIONS AND NEEDS

Agriculture (seasons) ~ 1rsquo000rsquo000 s

Calendar (solstices equinoxes) ~ 100 rsquo000 s

Daily activities (professional social etc) ~ 1rsquo000 s

Determination of the longitude (sea navigation) ~ 1 s

Common electronic and telecommunication devices ~ 001 s

Advanced telecommunication devices ~ 0000rsquo001 s

Satellite navigation ~ 0000rsquo000rsquo001 s

Scientific research and primary metrology lt 0000rsquo000rsquo000rsquo1 s

Need of atomic clocks (in the device or to calibrate the device)

10-11

10-14

lt 10-14

13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Typically 5 or 10 MHz

9 192 631 770 Hz

Magnetic resonance

BLOC DIAGRAM OF AN ATOMIC CLOCK

Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator

bull Statistical and non-statistical analysis

Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo

Systematic bias

Frequency of the oscillator

Statistical fluctuations

STABILITY AND ACCURACY

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

0

13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ALLAN DEVIATION

Frequency of the oscillator

1 )(1 K

K

t

tK dttyy generalindivergesyvarianceTrue ky22

212

12 )()( kky yy deviationAllany )(

bull Different types of noise processes affect differently the Allan deviation

bull Different applications require different (in)stabilities at given time scales

y() tells us how the

oscillator under test compares to an ideal one

over the timescale

13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Magnetic resonance allows ldquospin fliprdquo

Magnetic resonance is a frequency selective phenomenon

Sig

nal

Probing frequency

Linewidth 0

0

0

Q

21

)(20

NSQ

Iy

BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE

J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981

Allan deviation

0

RT1

0

R resonance laquodurationraquo

13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Discriminatorslope D

Detection noise

Frequency noise

The most important parameters for the clockperformances are

The resonancequality factor Q

The signal to noise ratio SN

RELEVANT PARAMETERS OF THE RESONANCE SIGNAL

13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

BLOCH VECTOR FORMALISM (SEMI-CLASSIC)

2E

1E

The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field

Microwave transitions optical transitions 2 pulses etc

Atom (or ensemble of atoms)

Interacting field (RF microwave optical)

Bloch vector (fictitious spin)

tie

12 EE

spopulationofdifferencequadratureindipoleatomic

phaseindipoleatomic

wvu

s

R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)

13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHAT HAPPENS IN AN ATOMIC CLOCK

Generalised magnetic resonance allows ldquospin flipsrdquo

It is a frequency selective phenomenon

In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator

In each type of clock it is realised on different species in various configurations and with different detection techniques

Sig

nal

Probing frequency

Linewidth

Or series of pulses such asThe Ramsey scheme (2)

13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS

- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations

- Put (or select) as many atoms as possible atoms in one(of the two) levels

- Perform the ldquomagnetic resonancerdquo (in one or more steps)

- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)

- Apply the necessary correction to the quartz oscillator

000

s

100

13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC BEAM FREQUENCY STANDARDS

Stern-Gerlach (State selection) and Ramsey interrogation

000

s

0)cos()sin(

0

0

tt

100

010

100

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 4Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RECENT NOBEL PRIZES IN PHYSICS RELATED TO THE FIELD

2012 S Haroche D Wineland

Control of individual quantum objects Photons and atoms

2005 J Hall T Haensch R Glauber

Laser precision spectroscopy Optical comb Quantum optic

1997 S Chu C Cohen-Tannoudji W Philips

Laser manipulation of atoms

1989 N Ramsey W Paul H Dehmelt

Separated oscillatory fields method for atomic clocks

Ion trap techniques

And several others in the previous years (Kastler optical pumping etc)

13th PSI Summer SchoolZug August 9-15 2014 5Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 6Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Definition in SI system

The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of cesium 133 (1967)

Hzh

EEFrequency 7706311929120

AtomsQuartz oscillator

Reference for the user (5 MHz)

Interrogation

Feed-back

F=4

F=36 Sfrac12

This would be the frequency of an atomic clock in which the atomic transition is not perturbed and the stabilisation ldquoperfectrdquo

ATOMIC CLOCK FREQUENCY-STABILIZED OSCILLATOR

00

1

TPeriod

13th PSI Summer SchoolZug August 9-15 2014 7Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY DO WE NEED TO STABILIZE THE QUARTZ

Slide from JohnVig tutorial on laquoQuartz crystalresonators and oscillatorsraquo

13th PSI Summer SchoolZug August 9-15 2014 8Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FIRST OVERVIEW OF APPLICATIONS AND NEEDS

Agriculture (seasons) ~ 1rsquo000rsquo000 s

Calendar (solstices equinoxes) ~ 100 rsquo000 s

Daily activities (professional social etc) ~ 1rsquo000 s

Determination of the longitude (sea navigation) ~ 1 s

Common electronic and telecommunication devices ~ 001 s

Advanced telecommunication devices ~ 0000rsquo001 s

Satellite navigation ~ 0000rsquo000rsquo001 s

Scientific research and primary metrology lt 0000rsquo000rsquo000rsquo1 s

Need of atomic clocks (in the device or to calibrate the device)

10-11

10-14

lt 10-14

13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Typically 5 or 10 MHz

9 192 631 770 Hz

Magnetic resonance

BLOC DIAGRAM OF AN ATOMIC CLOCK

Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator

bull Statistical and non-statistical analysis

Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo

Systematic bias

Frequency of the oscillator

Statistical fluctuations

STABILITY AND ACCURACY

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

0

13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ALLAN DEVIATION

Frequency of the oscillator

1 )(1 K

K

t

tK dttyy generalindivergesyvarianceTrue ky22

212

12 )()( kky yy deviationAllany )(

bull Different types of noise processes affect differently the Allan deviation

bull Different applications require different (in)stabilities at given time scales

y() tells us how the

oscillator under test compares to an ideal one

over the timescale

13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Magnetic resonance allows ldquospin fliprdquo

Magnetic resonance is a frequency selective phenomenon

Sig

nal

Probing frequency

Linewidth 0

0

0

Q

21

)(20

NSQ

Iy

BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE

J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981

Allan deviation

0

RT1

0

R resonance laquodurationraquo

13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Discriminatorslope D

Detection noise

Frequency noise

The most important parameters for the clockperformances are

The resonancequality factor Q

The signal to noise ratio SN

RELEVANT PARAMETERS OF THE RESONANCE SIGNAL

13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

BLOCH VECTOR FORMALISM (SEMI-CLASSIC)

2E

1E

The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field

Microwave transitions optical transitions 2 pulses etc

Atom (or ensemble of atoms)

Interacting field (RF microwave optical)

Bloch vector (fictitious spin)

tie

12 EE

spopulationofdifferencequadratureindipoleatomic

phaseindipoleatomic

wvu

s

R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)

13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHAT HAPPENS IN AN ATOMIC CLOCK

Generalised magnetic resonance allows ldquospin flipsrdquo

It is a frequency selective phenomenon

In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator

In each type of clock it is realised on different species in various configurations and with different detection techniques

Sig

nal

Probing frequency

Linewidth

Or series of pulses such asThe Ramsey scheme (2)

13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS

- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations

- Put (or select) as many atoms as possible atoms in one(of the two) levels

- Perform the ldquomagnetic resonancerdquo (in one or more steps)

- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)

- Apply the necessary correction to the quartz oscillator

000

s

100

13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC BEAM FREQUENCY STANDARDS

Stern-Gerlach (State selection) and Ramsey interrogation

000

s

0)cos()sin(

0

0

tt

100

010

100

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 5Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 6Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Definition in SI system

The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of cesium 133 (1967)

Hzh

EEFrequency 7706311929120

AtomsQuartz oscillator

Reference for the user (5 MHz)

Interrogation

Feed-back

F=4

F=36 Sfrac12

This would be the frequency of an atomic clock in which the atomic transition is not perturbed and the stabilisation ldquoperfectrdquo

ATOMIC CLOCK FREQUENCY-STABILIZED OSCILLATOR

00

1

TPeriod

13th PSI Summer SchoolZug August 9-15 2014 7Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY DO WE NEED TO STABILIZE THE QUARTZ

Slide from JohnVig tutorial on laquoQuartz crystalresonators and oscillatorsraquo

13th PSI Summer SchoolZug August 9-15 2014 8Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FIRST OVERVIEW OF APPLICATIONS AND NEEDS

Agriculture (seasons) ~ 1rsquo000rsquo000 s

Calendar (solstices equinoxes) ~ 100 rsquo000 s

Daily activities (professional social etc) ~ 1rsquo000 s

Determination of the longitude (sea navigation) ~ 1 s

Common electronic and telecommunication devices ~ 001 s

Advanced telecommunication devices ~ 0000rsquo001 s

Satellite navigation ~ 0000rsquo000rsquo001 s

Scientific research and primary metrology lt 0000rsquo000rsquo000rsquo1 s

Need of atomic clocks (in the device or to calibrate the device)

10-11

10-14

lt 10-14

13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Typically 5 or 10 MHz

9 192 631 770 Hz

Magnetic resonance

BLOC DIAGRAM OF AN ATOMIC CLOCK

Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator

bull Statistical and non-statistical analysis

Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo

Systematic bias

Frequency of the oscillator

Statistical fluctuations

STABILITY AND ACCURACY

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

0

13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ALLAN DEVIATION

Frequency of the oscillator

1 )(1 K

K

t

tK dttyy generalindivergesyvarianceTrue ky22

212

12 )()( kky yy deviationAllany )(

bull Different types of noise processes affect differently the Allan deviation

bull Different applications require different (in)stabilities at given time scales

y() tells us how the

oscillator under test compares to an ideal one

over the timescale

13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Magnetic resonance allows ldquospin fliprdquo

Magnetic resonance is a frequency selective phenomenon

Sig

nal

Probing frequency

Linewidth 0

0

0

Q

21

)(20

NSQ

Iy

BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE

J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981

Allan deviation

0

RT1

0

R resonance laquodurationraquo

13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Discriminatorslope D

Detection noise

Frequency noise

The most important parameters for the clockperformances are

The resonancequality factor Q

The signal to noise ratio SN

RELEVANT PARAMETERS OF THE RESONANCE SIGNAL

13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

BLOCH VECTOR FORMALISM (SEMI-CLASSIC)

2E

1E

The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field

Microwave transitions optical transitions 2 pulses etc

Atom (or ensemble of atoms)

Interacting field (RF microwave optical)

Bloch vector (fictitious spin)

tie

12 EE

spopulationofdifferencequadratureindipoleatomic

phaseindipoleatomic

wvu

s

R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)

13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHAT HAPPENS IN AN ATOMIC CLOCK

Generalised magnetic resonance allows ldquospin flipsrdquo

It is a frequency selective phenomenon

In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator

In each type of clock it is realised on different species in various configurations and with different detection techniques

Sig

nal

Probing frequency

Linewidth

Or series of pulses such asThe Ramsey scheme (2)

13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS

- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations

- Put (or select) as many atoms as possible atoms in one(of the two) levels

- Perform the ldquomagnetic resonancerdquo (in one or more steps)

- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)

- Apply the necessary correction to the quartz oscillator

000

s

100

13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC BEAM FREQUENCY STANDARDS

Stern-Gerlach (State selection) and Ramsey interrogation

000

s

0)cos()sin(

0

0

tt

100

010

100

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 6Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Definition in SI system

The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of cesium 133 (1967)

Hzh

EEFrequency 7706311929120

AtomsQuartz oscillator

Reference for the user (5 MHz)

Interrogation

Feed-back

F=4

F=36 Sfrac12

This would be the frequency of an atomic clock in which the atomic transition is not perturbed and the stabilisation ldquoperfectrdquo

ATOMIC CLOCK FREQUENCY-STABILIZED OSCILLATOR

00

1

TPeriod

13th PSI Summer SchoolZug August 9-15 2014 7Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY DO WE NEED TO STABILIZE THE QUARTZ

Slide from JohnVig tutorial on laquoQuartz crystalresonators and oscillatorsraquo

13th PSI Summer SchoolZug August 9-15 2014 8Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FIRST OVERVIEW OF APPLICATIONS AND NEEDS

Agriculture (seasons) ~ 1rsquo000rsquo000 s

Calendar (solstices equinoxes) ~ 100 rsquo000 s

Daily activities (professional social etc) ~ 1rsquo000 s

Determination of the longitude (sea navigation) ~ 1 s

Common electronic and telecommunication devices ~ 001 s

Advanced telecommunication devices ~ 0000rsquo001 s

Satellite navigation ~ 0000rsquo000rsquo001 s

Scientific research and primary metrology lt 0000rsquo000rsquo000rsquo1 s

Need of atomic clocks (in the device or to calibrate the device)

10-11

10-14

lt 10-14

13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Typically 5 or 10 MHz

9 192 631 770 Hz

Magnetic resonance

BLOC DIAGRAM OF AN ATOMIC CLOCK

Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator

bull Statistical and non-statistical analysis

Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo

Systematic bias

Frequency of the oscillator

Statistical fluctuations

STABILITY AND ACCURACY

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

0

13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ALLAN DEVIATION

Frequency of the oscillator

1 )(1 K

K

t

tK dttyy generalindivergesyvarianceTrue ky22

212

12 )()( kky yy deviationAllany )(

bull Different types of noise processes affect differently the Allan deviation

bull Different applications require different (in)stabilities at given time scales

y() tells us how the

oscillator under test compares to an ideal one

over the timescale

13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Magnetic resonance allows ldquospin fliprdquo

Magnetic resonance is a frequency selective phenomenon

Sig

nal

Probing frequency

Linewidth 0

0

0

Q

21

)(20

NSQ

Iy

BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE

J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981

Allan deviation

0

RT1

0

R resonance laquodurationraquo

13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Discriminatorslope D

Detection noise

Frequency noise

The most important parameters for the clockperformances are

The resonancequality factor Q

The signal to noise ratio SN

RELEVANT PARAMETERS OF THE RESONANCE SIGNAL

13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

BLOCH VECTOR FORMALISM (SEMI-CLASSIC)

2E

1E

The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field

Microwave transitions optical transitions 2 pulses etc

Atom (or ensemble of atoms)

Interacting field (RF microwave optical)

Bloch vector (fictitious spin)

tie

12 EE

spopulationofdifferencequadratureindipoleatomic

phaseindipoleatomic

wvu

s

R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)

13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHAT HAPPENS IN AN ATOMIC CLOCK

Generalised magnetic resonance allows ldquospin flipsrdquo

It is a frequency selective phenomenon

In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator

In each type of clock it is realised on different species in various configurations and with different detection techniques

Sig

nal

Probing frequency

Linewidth

Or series of pulses such asThe Ramsey scheme (2)

13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS

- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations

- Put (or select) as many atoms as possible atoms in one(of the two) levels

- Perform the ldquomagnetic resonancerdquo (in one or more steps)

- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)

- Apply the necessary correction to the quartz oscillator

000

s

100

13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC BEAM FREQUENCY STANDARDS

Stern-Gerlach (State selection) and Ramsey interrogation

000

s

0)cos()sin(

0

0

tt

100

010

100

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 7Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY DO WE NEED TO STABILIZE THE QUARTZ

Slide from JohnVig tutorial on laquoQuartz crystalresonators and oscillatorsraquo

13th PSI Summer SchoolZug August 9-15 2014 8Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FIRST OVERVIEW OF APPLICATIONS AND NEEDS

Agriculture (seasons) ~ 1rsquo000rsquo000 s

Calendar (solstices equinoxes) ~ 100 rsquo000 s

Daily activities (professional social etc) ~ 1rsquo000 s

Determination of the longitude (sea navigation) ~ 1 s

Common electronic and telecommunication devices ~ 001 s

Advanced telecommunication devices ~ 0000rsquo001 s

Satellite navigation ~ 0000rsquo000rsquo001 s

Scientific research and primary metrology lt 0000rsquo000rsquo000rsquo1 s

Need of atomic clocks (in the device or to calibrate the device)

10-11

10-14

lt 10-14

13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Typically 5 or 10 MHz

9 192 631 770 Hz

Magnetic resonance

BLOC DIAGRAM OF AN ATOMIC CLOCK

Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator

bull Statistical and non-statistical analysis

Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo

Systematic bias

Frequency of the oscillator

Statistical fluctuations

STABILITY AND ACCURACY

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

0

13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ALLAN DEVIATION

Frequency of the oscillator

1 )(1 K

K

t

tK dttyy generalindivergesyvarianceTrue ky22

212

12 )()( kky yy deviationAllany )(

bull Different types of noise processes affect differently the Allan deviation

bull Different applications require different (in)stabilities at given time scales

y() tells us how the

oscillator under test compares to an ideal one

over the timescale

13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Magnetic resonance allows ldquospin fliprdquo

Magnetic resonance is a frequency selective phenomenon

Sig

nal

Probing frequency

Linewidth 0

0

0

Q

21

)(20

NSQ

Iy

BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE

J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981

Allan deviation

0

RT1

0

R resonance laquodurationraquo

13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Discriminatorslope D

Detection noise

Frequency noise

The most important parameters for the clockperformances are

The resonancequality factor Q

The signal to noise ratio SN

RELEVANT PARAMETERS OF THE RESONANCE SIGNAL

13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

BLOCH VECTOR FORMALISM (SEMI-CLASSIC)

2E

1E

The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field

Microwave transitions optical transitions 2 pulses etc

Atom (or ensemble of atoms)

Interacting field (RF microwave optical)

Bloch vector (fictitious spin)

tie

12 EE

spopulationofdifferencequadratureindipoleatomic

phaseindipoleatomic

wvu

s

R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)

13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHAT HAPPENS IN AN ATOMIC CLOCK

Generalised magnetic resonance allows ldquospin flipsrdquo

It is a frequency selective phenomenon

In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator

In each type of clock it is realised on different species in various configurations and with different detection techniques

Sig

nal

Probing frequency

Linewidth

Or series of pulses such asThe Ramsey scheme (2)

13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS

- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations

- Put (or select) as many atoms as possible atoms in one(of the two) levels

- Perform the ldquomagnetic resonancerdquo (in one or more steps)

- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)

- Apply the necessary correction to the quartz oscillator

000

s

100

13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC BEAM FREQUENCY STANDARDS

Stern-Gerlach (State selection) and Ramsey interrogation

000

s

0)cos()sin(

0

0

tt

100

010

100

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 8Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FIRST OVERVIEW OF APPLICATIONS AND NEEDS

Agriculture (seasons) ~ 1rsquo000rsquo000 s

Calendar (solstices equinoxes) ~ 100 rsquo000 s

Daily activities (professional social etc) ~ 1rsquo000 s

Determination of the longitude (sea navigation) ~ 1 s

Common electronic and telecommunication devices ~ 001 s

Advanced telecommunication devices ~ 0000rsquo001 s

Satellite navigation ~ 0000rsquo000rsquo001 s

Scientific research and primary metrology lt 0000rsquo000rsquo000rsquo1 s

Need of atomic clocks (in the device or to calibrate the device)

10-11

10-14

lt 10-14

13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Typically 5 or 10 MHz

9 192 631 770 Hz

Magnetic resonance

BLOC DIAGRAM OF AN ATOMIC CLOCK

Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator

bull Statistical and non-statistical analysis

Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo

Systematic bias

Frequency of the oscillator

Statistical fluctuations

STABILITY AND ACCURACY

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

0

13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ALLAN DEVIATION

Frequency of the oscillator

1 )(1 K

K

t

tK dttyy generalindivergesyvarianceTrue ky22

212

12 )()( kky yy deviationAllany )(

bull Different types of noise processes affect differently the Allan deviation

bull Different applications require different (in)stabilities at given time scales

y() tells us how the

oscillator under test compares to an ideal one

over the timescale

13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Magnetic resonance allows ldquospin fliprdquo

Magnetic resonance is a frequency selective phenomenon

Sig

nal

Probing frequency

Linewidth 0

0

0

Q

21

)(20

NSQ

Iy

BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE

J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981

Allan deviation

0

RT1

0

R resonance laquodurationraquo

13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Discriminatorslope D

Detection noise

Frequency noise

The most important parameters for the clockperformances are

The resonancequality factor Q

The signal to noise ratio SN

RELEVANT PARAMETERS OF THE RESONANCE SIGNAL

13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

BLOCH VECTOR FORMALISM (SEMI-CLASSIC)

2E

1E

The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field

Microwave transitions optical transitions 2 pulses etc

Atom (or ensemble of atoms)

Interacting field (RF microwave optical)

Bloch vector (fictitious spin)

tie

12 EE

spopulationofdifferencequadratureindipoleatomic

phaseindipoleatomic

wvu

s

R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)

13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHAT HAPPENS IN AN ATOMIC CLOCK

Generalised magnetic resonance allows ldquospin flipsrdquo

It is a frequency selective phenomenon

In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator

In each type of clock it is realised on different species in various configurations and with different detection techniques

Sig

nal

Probing frequency

Linewidth

Or series of pulses such asThe Ramsey scheme (2)

13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS

- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations

- Put (or select) as many atoms as possible atoms in one(of the two) levels

- Perform the ldquomagnetic resonancerdquo (in one or more steps)

- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)

- Apply the necessary correction to the quartz oscillator

000

s

100

13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC BEAM FREQUENCY STANDARDS

Stern-Gerlach (State selection) and Ramsey interrogation

000

s

0)cos()sin(

0

0

tt

100

010

100

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 9Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Typically 5 or 10 MHz

9 192 631 770 Hz

Magnetic resonance

BLOC DIAGRAM OF AN ATOMIC CLOCK

Adapted from Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator

bull Statistical and non-statistical analysis

Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo

Systematic bias

Frequency of the oscillator

Statistical fluctuations

STABILITY AND ACCURACY

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

0

13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ALLAN DEVIATION

Frequency of the oscillator

1 )(1 K

K

t

tK dttyy generalindivergesyvarianceTrue ky22

212

12 )()( kky yy deviationAllany )(

bull Different types of noise processes affect differently the Allan deviation

bull Different applications require different (in)stabilities at given time scales

y() tells us how the

oscillator under test compares to an ideal one

over the timescale

13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Magnetic resonance allows ldquospin fliprdquo

Magnetic resonance is a frequency selective phenomenon

Sig

nal

Probing frequency

Linewidth 0

0

0

Q

21

)(20

NSQ

Iy

BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE

J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981

Allan deviation

0

RT1

0

R resonance laquodurationraquo

13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Discriminatorslope D

Detection noise

Frequency noise

The most important parameters for the clockperformances are

The resonancequality factor Q

The signal to noise ratio SN

RELEVANT PARAMETERS OF THE RESONANCE SIGNAL

13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

BLOCH VECTOR FORMALISM (SEMI-CLASSIC)

2E

1E

The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field

Microwave transitions optical transitions 2 pulses etc

Atom (or ensemble of atoms)

Interacting field (RF microwave optical)

Bloch vector (fictitious spin)

tie

12 EE

spopulationofdifferencequadratureindipoleatomic

phaseindipoleatomic

wvu

s

R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)

13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHAT HAPPENS IN AN ATOMIC CLOCK

Generalised magnetic resonance allows ldquospin flipsrdquo

It is a frequency selective phenomenon

In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator

In each type of clock it is realised on different species in various configurations and with different detection techniques

Sig

nal

Probing frequency

Linewidth

Or series of pulses such asThe Ramsey scheme (2)

13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS

- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations

- Put (or select) as many atoms as possible atoms in one(of the two) levels

- Perform the ldquomagnetic resonancerdquo (in one or more steps)

- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)

- Apply the necessary correction to the quartz oscillator

000

s

100

13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC BEAM FREQUENCY STANDARDS

Stern-Gerlach (State selection) and Ramsey interrogation

000

s

0)cos()sin(

0

0

tt

100

010

100

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 10Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

How to measure evaluate the stability and accuracybull By comparing to a more stable andor accurate oscillator

bull Statistical and non-statistical analysis

Inspired by John Vig tutorial on laquoQuartz crystalresonators and oscillatorsraquo

Systematic bias

Frequency of the oscillator

Statistical fluctuations

STABILITY AND ACCURACY

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

Stable but not accurate

Not stable and not accurate

Not stable but (relatively) accurate

Stable and accurate

0

13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ALLAN DEVIATION

Frequency of the oscillator

1 )(1 K

K

t

tK dttyy generalindivergesyvarianceTrue ky22

212

12 )()( kky yy deviationAllany )(

bull Different types of noise processes affect differently the Allan deviation

bull Different applications require different (in)stabilities at given time scales

y() tells us how the

oscillator under test compares to an ideal one

over the timescale

13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Magnetic resonance allows ldquospin fliprdquo

Magnetic resonance is a frequency selective phenomenon

Sig

nal

Probing frequency

Linewidth 0

0

0

Q

21

)(20

NSQ

Iy

BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE

J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981

Allan deviation

0

RT1

0

R resonance laquodurationraquo

13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Discriminatorslope D

Detection noise

Frequency noise

The most important parameters for the clockperformances are

The resonancequality factor Q

The signal to noise ratio SN

RELEVANT PARAMETERS OF THE RESONANCE SIGNAL

13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

BLOCH VECTOR FORMALISM (SEMI-CLASSIC)

2E

1E

The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field

Microwave transitions optical transitions 2 pulses etc

Atom (or ensemble of atoms)

Interacting field (RF microwave optical)

Bloch vector (fictitious spin)

tie

12 EE

spopulationofdifferencequadratureindipoleatomic

phaseindipoleatomic

wvu

s

R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)

13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHAT HAPPENS IN AN ATOMIC CLOCK

Generalised magnetic resonance allows ldquospin flipsrdquo

It is a frequency selective phenomenon

In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator

In each type of clock it is realised on different species in various configurations and with different detection techniques

Sig

nal

Probing frequency

Linewidth

Or series of pulses such asThe Ramsey scheme (2)

13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS

- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations

- Put (or select) as many atoms as possible atoms in one(of the two) levels

- Perform the ldquomagnetic resonancerdquo (in one or more steps)

- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)

- Apply the necessary correction to the quartz oscillator

000

s

100

13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC BEAM FREQUENCY STANDARDS

Stern-Gerlach (State selection) and Ramsey interrogation

000

s

0)cos()sin(

0

0

tt

100

010

100

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 11Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ALLAN DEVIATION

Frequency of the oscillator

1 )(1 K

K

t

tK dttyy generalindivergesyvarianceTrue ky22

212

12 )()( kky yy deviationAllany )(

bull Different types of noise processes affect differently the Allan deviation

bull Different applications require different (in)stabilities at given time scales

y() tells us how the

oscillator under test compares to an ideal one

over the timescale

13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Magnetic resonance allows ldquospin fliprdquo

Magnetic resonance is a frequency selective phenomenon

Sig

nal

Probing frequency

Linewidth 0

0

0

Q

21

)(20

NSQ

Iy

BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE

J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981

Allan deviation

0

RT1

0

R resonance laquodurationraquo

13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Discriminatorslope D

Detection noise

Frequency noise

The most important parameters for the clockperformances are

The resonancequality factor Q

The signal to noise ratio SN

RELEVANT PARAMETERS OF THE RESONANCE SIGNAL

13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

BLOCH VECTOR FORMALISM (SEMI-CLASSIC)

2E

1E

The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field

Microwave transitions optical transitions 2 pulses etc

Atom (or ensemble of atoms)

Interacting field (RF microwave optical)

Bloch vector (fictitious spin)

tie

12 EE

spopulationofdifferencequadratureindipoleatomic

phaseindipoleatomic

wvu

s

R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)

13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHAT HAPPENS IN AN ATOMIC CLOCK

Generalised magnetic resonance allows ldquospin flipsrdquo

It is a frequency selective phenomenon

In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator

In each type of clock it is realised on different species in various configurations and with different detection techniques

Sig

nal

Probing frequency

Linewidth

Or series of pulses such asThe Ramsey scheme (2)

13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS

- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations

- Put (or select) as many atoms as possible atoms in one(of the two) levels

- Perform the ldquomagnetic resonancerdquo (in one or more steps)

- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)

- Apply the necessary correction to the quartz oscillator

000

s

100

13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC BEAM FREQUENCY STANDARDS

Stern-Gerlach (State selection) and Ramsey interrogation

000

s

0)cos()sin(

0

0

tt

100

010

100

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 12Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Magnetic resonance allows ldquospin fliprdquo

Magnetic resonance is a frequency selective phenomenon

Sig

nal

Probing frequency

Linewidth 0

0

0

Q

21

)(20

NSQ

Iy

BASIC PHYSICAL PRINCIPLE MAGNETIC RESONANCE

J Vanier L Bernier IEEE Trans on Instr and Meas Vol IM-30 No 4 Dec 1981

Allan deviation

0

RT1

0

R resonance laquodurationraquo

13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Discriminatorslope D

Detection noise

Frequency noise

The most important parameters for the clockperformances are

The resonancequality factor Q

The signal to noise ratio SN

RELEVANT PARAMETERS OF THE RESONANCE SIGNAL

13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

BLOCH VECTOR FORMALISM (SEMI-CLASSIC)

2E

1E

The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field

Microwave transitions optical transitions 2 pulses etc

Atom (or ensemble of atoms)

Interacting field (RF microwave optical)

Bloch vector (fictitious spin)

tie

12 EE

spopulationofdifferencequadratureindipoleatomic

phaseindipoleatomic

wvu

s

R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)

13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHAT HAPPENS IN AN ATOMIC CLOCK

Generalised magnetic resonance allows ldquospin flipsrdquo

It is a frequency selective phenomenon

In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator

In each type of clock it is realised on different species in various configurations and with different detection techniques

Sig

nal

Probing frequency

Linewidth

Or series of pulses such asThe Ramsey scheme (2)

13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS

- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations

- Put (or select) as many atoms as possible atoms in one(of the two) levels

- Perform the ldquomagnetic resonancerdquo (in one or more steps)

- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)

- Apply the necessary correction to the quartz oscillator

000

s

100

13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC BEAM FREQUENCY STANDARDS

Stern-Gerlach (State selection) and Ramsey interrogation

000

s

0)cos()sin(

0

0

tt

100

010

100

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 13Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Discriminatorslope D

Detection noise

Frequency noise

The most important parameters for the clockperformances are

The resonancequality factor Q

The signal to noise ratio SN

RELEVANT PARAMETERS OF THE RESONANCE SIGNAL

13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

BLOCH VECTOR FORMALISM (SEMI-CLASSIC)

2E

1E

The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field

Microwave transitions optical transitions 2 pulses etc

Atom (or ensemble of atoms)

Interacting field (RF microwave optical)

Bloch vector (fictitious spin)

tie

12 EE

spopulationofdifferencequadratureindipoleatomic

phaseindipoleatomic

wvu

s

R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)

13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHAT HAPPENS IN AN ATOMIC CLOCK

Generalised magnetic resonance allows ldquospin flipsrdquo

It is a frequency selective phenomenon

In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator

In each type of clock it is realised on different species in various configurations and with different detection techniques

Sig

nal

Probing frequency

Linewidth

Or series of pulses such asThe Ramsey scheme (2)

13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS

- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations

- Put (or select) as many atoms as possible atoms in one(of the two) levels

- Perform the ldquomagnetic resonancerdquo (in one or more steps)

- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)

- Apply the necessary correction to the quartz oscillator

000

s

100

13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC BEAM FREQUENCY STANDARDS

Stern-Gerlach (State selection) and Ramsey interrogation

000

s

0)cos()sin(

0

0

tt

100

010

100

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 14Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

BLOCH VECTOR FORMALISM (SEMI-CLASSIC)

2E

1E

The state of an atom (2 levels) may be represented with a vector (ldquoBloch vectorrdquo or ldquoFictitious spinrdquo) and its behavior when interacting with a resonant field as a magnetic moment in a magnetic field

Microwave transitions optical transitions 2 pulses etc

Atom (or ensemble of atoms)

Interacting field (RF microwave optical)

Bloch vector (fictitious spin)

tie

12 EE

spopulationofdifferencequadratureindipoleatomic

phaseindipoleatomic

wvu

s

R Feynman F Vernon R Hellwarth ldquoGeometrical representation of the Schroumldinger equation for solving Maser problemsrdquo J App Phys Vol 28 p 49 (1957)

13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHAT HAPPENS IN AN ATOMIC CLOCK

Generalised magnetic resonance allows ldquospin flipsrdquo

It is a frequency selective phenomenon

In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator

In each type of clock it is realised on different species in various configurations and with different detection techniques

Sig

nal

Probing frequency

Linewidth

Or series of pulses such asThe Ramsey scheme (2)

13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS

- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations

- Put (or select) as many atoms as possible atoms in one(of the two) levels

- Perform the ldquomagnetic resonancerdquo (in one or more steps)

- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)

- Apply the necessary correction to the quartz oscillator

000

s

100

13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC BEAM FREQUENCY STANDARDS

Stern-Gerlach (State selection) and Ramsey interrogation

000

s

0)cos()sin(

0

0

tt

100

010

100

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 15Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHAT HAPPENS IN AN ATOMIC CLOCK

Generalised magnetic resonance allows ldquospin flipsrdquo

It is a frequency selective phenomenon

In an atomic clock you exploit this phenomenon to frequency stabilise a quartz oscillator

In each type of clock it is realised on different species in various configurations and with different detection techniques

Sig

nal

Probing frequency

Linewidth

Or series of pulses such asThe Ramsey scheme (2)

13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS

- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations

- Put (or select) as many atoms as possible atoms in one(of the two) levels

- Perform the ldquomagnetic resonancerdquo (in one or more steps)

- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)

- Apply the necessary correction to the quartz oscillator

000

s

100

13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC BEAM FREQUENCY STANDARDS

Stern-Gerlach (State selection) and Ramsey interrogation

000

s

0)cos()sin(

0

0

tt

100

010

100

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 16Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GENERAL SCHEME (OR SEQUENCE) IN ATOMIC CLOCKS

- Have the atoms available and as isolated as possible fromthe ldquooutsiderdquo undesired interactions perturbations

- Put (or select) as many atoms as possible atoms in one(of the two) levels

- Perform the ldquomagnetic resonancerdquo (in one or more steps)

- Detect the result of the ldquomagnetic resonancerdquo (leveltransition)

- Apply the necessary correction to the quartz oscillator

000

s

100

13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC BEAM FREQUENCY STANDARDS

Stern-Gerlach (State selection) and Ramsey interrogation

000

s

0)cos()sin(

0

0

tt

100

010

100

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 17Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC BEAM FREQUENCY STANDARDS

Stern-Gerlach (State selection) and Ramsey interrogation

000

s

0)cos()sin(

0

0

tt

100

010

100

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 18Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Primary (Cs) ndash Secondary

bull Passive ndash Active (H-Maser)

bull Commercial (Rb Cs H)

bull Ground or Space applications

bull Laboratory ndash ldquoIn developmentrdquo

bull Microwave ndash Optical

bull Neutral atoms ndash Ions ndash Molecules ndash Nuclear - hellip

CATEGORIES OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 19Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Radioastronomy Geodesy

(VLBI Radioastron etc)

Scientific Research Instrumentation

(Microgravity ACES HYPER etc)

Navigation amp Positioning

(Galileo GPS GLONASS etc)

Telecommunications

(Networks synchronisation etc)

Power distribution networks

(Smart power grids)

Metrology Time scales

(Primary and secondary standards H-Masers)

MAIN FIELDS OF APPLICATIONS OF ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 20Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

CESIUM BEAM STANDARD

10-11 1s but accurate and very stable in the long term

Rabi pedestal

Ramsey fringe

RTLinewidth 1

0

atomsofspeedcavityofLengthLTR

v

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 21Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY SCHEME (SEPARATED OSCILLATORY FIELDS METHOD )

For a monokinetic beam

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 22Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

LASER-PUMPED BEAM STANDARDS

Optical pumping

1st Rabi(2) pulse

Free precession

2nd Rabi(2) pulse

Detection

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 23Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

)](cos[)( 0 rtEecirctrE L

forcepressureradiationoredissipativ

stab

forcedipolarorreactive

stab rrEvdecircrEudecircF )()()( 00

~ light-shift ~ absorption

Optical molassesOptical trapping (lattice tweezers etc)

Motivations reduce the Doppler effect increase interaction time etcRT

10

LASER RADIATIVE FORCES

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 24Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

COLD ATOMIC BEAM CLOCKS (FOUNTAINS)

-100 -50 0 50 10000

01

02

03

04

010101 142506

Lock

-in s

igna

l

M icrowave frequency detuning

Thermal beam v = 100 ms TR = 5 ms = 100 Hz

Cold fountain v = 4 ms TR = 05 s = 1 Hz

Next step microgravity (TR = 10 s = 01 Hz)

RTLinewidth 1 0

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 25Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

PRIMARY FREQUENCY STANDARDS

Systematic bias

Frequency

Statistical fluctuations

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 26Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

ATOMIC TIME (TAI) AND ASTRONOMICAL TIME (UTC)

Leap second

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 27Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RUBIDIUM VAPOUR CELL STANDARD

xmicrowaveresonatoramp source

vapourcell

Discharge lamp

QuartzLO

S

P

Double resonance

light

-wave

Tran

smitt

ed li

ght

Microwave frequency

kHz

10-11 1s10-13 10rsquo000s

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 28Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Rb87 LampRb85 filtre

Rb87 resonance cell

deacutetector

Microwave cavity

5304x106 5306x106 5308x106 5310x106 5312x1060108

0112

0116

0120

0124

0128

Tra

nsm

itted

ligh

t [V

on

10k

]

684 GHz - Synthesiser frequency [Hz]

S

P

Double resonance

light

-wave

DOUBLE RESONANCE (WITH A DISCHARGE LAMP)

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 29Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLES OF RB CLOCKS (OBSERVATOIRE NE 1985-1995)

Next generation replace the discharge lamp with a laser for a more efficient optical pumpingCurrently commercialized by Spectratime-Orolia Used in the GALILEO navigation system

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 30Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

HYDROGEN MASER

100 kg

() 1

10-13

1s

10-15

100s

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 31Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

VLBI (VERY LONG BASE INTERFEROMETRY)

H-Masers (10-15 ~1000-10rsquo000 s) are used to increase the resolution

Angular resolution ~ Diameter

1 radio-telescope ~ 1 mrad (10-3 rad)

2 radio-telescopes ~ 1 nrad (10-9 rad)

Earth rotation 1 mrad rarr 6 km rarr 14 s

cB sin

B

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 32Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Increase the Baseline B from 30rsquo000 to 300rsquo000 km by putting one of the telescope (and one Maser) in space

RADIOASTRON MISSION (SPACE VLBI)

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 33Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

FUNDAMENTAL PHYSICS IN SPACE

Atomic Clock Ensemble in Space

Micro-gravity

Relativity

0

11Q

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 34Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Application GALILEO

1ns (10-14) time error

darr30 cm position error

Goal 10-14 stability 10rsquo000 s(keeping 1 ns over one orbit)

darr10-12 1 s

18 kg 28 L 710-13 1 s

SPACE PASSIVE HYDROGEN MASER FOR GNSS

GNSS Global Navigation Satellite System

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 35Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

GALILEO (EUROPEAN SATELLITE NAVIGATION SYSTEM)

In space Rubidium passive Hydrogen Maser (1deg generation)

On earth (quartz) Rubidium Cesium beams active H Masers (1deg generation)

GIOVE-A (launched 28 Dec 2005) GIOVE-B (launched 26 April 08)

2011 and 2012 launch of first operational satellites (IOV ndash In Orbit Validation)

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 36Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

WHY RB CLOCK AND PASSIVE H MASER ON GALILEO

10-16

10-15

10-14

10-13

10-12

10-11

10-10

1 10 100 1000 104 105 106 107

Cs beam magneticCs-beam laser H-maser activeH-maser passiveRb cell lampRb or Cs cell laser CS cold

Time interval (s)

Alla

n de

vFor 30 cm accuracy

Maximal Time error

1 nanosecond for

1s lt lt 20rsquo000 s

1410)00020( sy

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 37Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OUTLINE OF THE TALK

1) Introduction to atomic frequency standards

Basic (functional and physical) principles

Examples and applications of frequency standards

2) Current trends in the field

Optical frequency standards

Chip-scale atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 38Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RTQ

0

11

OPTICAL FREQUENCY STANDARDS

01010 rarr1015 Hz

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 39Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

MICROWAVE AND OPTICAL CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 40Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OPTICAL CLOCKS WITH SINGLE IONS AND QUANTUM LOGIC

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 41Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

EXAMPLE OF MORE RECENT ACHIEVEMENTS

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 42Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

STABILISED LASERS amp COMB FOR A (SPACE) CO2 LIDAR

R Matthey F Gruet S Schilt G Mileti Rb-based Stabilized LaserSystem as Frequency Reference for CO2 Monitoring Proceedingsof the European Frequency and Time Forum (EFTF) NeuchacirctelJune 23-27 (2014)

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 43Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER COMPACT AND MINIATURE STABILISED LASERS

F Gruet F Vecchio CAffolderbach Y Peacutetremand NF de Rooij T Maeder G MiletiA Miniature Frequency-StabilizedVCSEL system emitting at 795nm based on LTCC modulessubmitted to Optics and Lasersin Engineering 51 8 1023ndash1027 (2013)

R Matthey L Stauffer PGiaccari A Pollini L BaletG Mileti Assembly Techniquefor Miniaturized OpticalDevices Towards SpaceQualification Proc of theInternational Conference onSpace Optics (ICSO) Ajaccio(2012)

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 44Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

RAMSEY INTERROGATION IN A CELL STANDARD

ν-ν0(Hz)Pr

obab

ility

pTRamsey

T1T1

Time-domain Ramsey scheme

bull Optical pumping( TP)bull Microwave pulse interrogation

(T1 TRamsey) bull Optical Detection (Td)

Rb vapor cell

Advantages Compactness Narrow linewidth Negligible light shift

Td

Det

Tp

tπ2 pulse

π2 pulse

S Kang C Affolderbach F Gruet M Gharavipour C E Calosso G Mileti Pulsed optical pumping in a Rb vapor cell using a compact magnetron-type microwave cavity EFTF-2014

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 45Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Bring atomic timing precision to the size and power range previously covered by quartz oscillators

PrimaryStandard

CommercialBeam Clock

CompactAtomic Clock

WristwatchQuartz

Accuracy 10‐15 10‐13 10‐11 10‐7 10‐5Timing error 10nsyr 1syr 01sday 100sday 1sdaySize 107 cm3 104 cm3 100 cm3 1‐10 cm3 10 mm3

Power kW 100rsquos W 1 W 100 mW 10 WCost gt$1 M $50 k $2000 $100 $1

PrecisionQuartz

Decreasing performance and sizepowercost

MiniatureAtomic Clock

New clocks

10‐101sday 10 cm3

120mW$300

MINIATURE ATOMIC CLOCKS

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 46Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

Dia=5 mm

L =10x10 mm 200 - 500 um

500-2000 um

Silicon wafer

Photolithography and cavity etching by DRIE

Wafer-level anodic bonding of Si with glass

Dicing

Cell closing Anodic bonding of glass lid

200 - 500 um

Rb deposition

NEUCHAcircTEL ANODIC BONDING TECHNOLOGY

IMT-SAMLAB

J Di Francesco F Gruet CSchori C Affolderbach RMatthey G Mileti Y SalvadeacuteY Petremand N De RooijEvaluation of the frequencystability of a VCSEL locked toa micro-fabricated Rubidiumvapour cell SPIE PhotonicsEurope Bruxelles April(2010)

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 47Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

SPECIAL MINIATURE CELLSIMT-SAMLAB

4-mm size Rb cellsMicro-fabrication technology for precise

control of cell geometryMulti-stack anodic bonding Thick glass core wafer

2 Si layers + 2 glass windows 4 steps of anodic bonding

Indium cell sealingLow-temperature sealing (le 140degC) alkali control amp wall coatings

Working alkali cells

5mm

R Straessle M Pellaton YPeacutetremand C Affolderbach DBriand G Mileti and N F de RooijLow-Temperature Indium HermeticSealing of Alkali Vapor-Cells for ChipScale Atomic Clocks submitted toJournal of Applied Physics 113issue 6 0645011-8 (2013)

Y Peacutetremand C Affolderbach R Straessle MPellaton D Briand G Mileti and N F de RooijMicrofabricated rubidium vapour-cell with athick glass core for small scale atomic clockapplications Journal of Micromechanics andMicroengineering 22 025013 (2012)

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 48Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Miniature cesium atomic clock

CPT (Coherent population trapping) technique

Applications

Telecom (4G LTE base stations)

Smart grid (power distribution)

Product specifications

Superior frequency and time stability 1 microsday

Compact size 51x51x18 mm3

Low power 2W

Lower price 400 CHF

Cs cell + Ne

4 Cs cell + Ne

Filter Photo-diode

Magnetic shield + coil

Pre-amplifier

Current source

RF generator= hf2

Quartz oscillator

High pass filter

Low pass filter

User 20 MHz

Laser

Clock implementation

51 mm

51 mm

15 mm

Prototype picture

QUANTIME ndash A MINIATURE CESIUM ATOMIC CLOCK USING CPT TECHNIQUE FOR TELECOM APPLICATIONS (CTI REF 13rsquo8182)

Y Zhao S Tanner A Casagrande L Schneller C Affolderbach G Mileti P-A Farine A 46-GHz 15-mW FrequencySynthesizer CMOS ASIC for Miniature Atomic Clocks IEEE Transactions on Microwave Theory and Techniques (2014)

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 49Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

OTHER RECENT DEVELOPMENTS

Imaging of microwave field and atoms relaxation timeA Horsley G-X Du M Pellaton C Affolderbach G Mileti P Treutlein Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell Physical Review A 88 063407 (2013)

Microfabricated discharge lampsV Venkatraman S Kang C Affolderbach H Shea and G Mileti Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source Applied Physics Letters 104 054104 (2014)

Microfabricated cells with wall coatingR Straessle M Pellaton C Affolderbach Y Peacutetremand D Briand G Mileti and N F de Rooij Microfabricated Alkali Vapor Cell with Anti-Relaxation Wall Coating Applied Physics Letters 105 043502 (2014)

Double resonance with miniature microwave cavity and Rb cellM Violetti M Pellaton F Merli JndashF Zuumlrcher C Affolderbach G Mileti A K Skrivervik The Micro Loop-Gap Resonator A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks IEEE Journal of Sensors 14 9 (2014)

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 50Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Summary bull Thanks to the latest discoveries in atomic physics and photonics (or photon engineering)

the precision of atomic clocks is being improved down to 10-16 and beyond

bull More precisely it is the manipulation of atoms photons and the availability of tunablelaser sources and optical combs which is allowing such dramatic improvements

bull Atomic clocks (and stabilized lasers) are key instruments for fundamental physicsexperiments on ground and in space

bull Compact high performance and miniature atomic clocks find many applications inevery day life (positioning telecoms etc)

bull Micro-fabrication techniques are crucial for extreme miniaturization

bull With its tradition in Time keeping precision mechanics micro-technology opticalmetrology and space science amp technology Switzerland makes crucial contributions tothis domain

RTstabilityIn

00

0 1)(

TR cooling0 going optical

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 51Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

bull Jacques Vanier Claude Audoin ldquoThe Quantum Physics of Atomic Frequency Standardsrdquo Bristol Adam Hilger 1989

bull Claude Audoin Bernard Guinot Stephen Lyle ldquoThe Measurement of Time Time Frequency and the Atomic Clock rdquo Cambridge (Original in french Masson 1998)

bull Fritz Riehle ldquoFrequency standards ndash Basics and applicationsrdquo Wiley-VCH 2005

bull Special issue of Metrologia ldquoSpecial issue fifty years of atomic time-keeping 1955 to 2005rdquo Volume 42 Number 3 June 2005

Time amp Frequency conferences proceedings (including tutorials)

wwweftforg (free) rarr EFTF-2014 in Neuchacirctel (June 23-26 2014)wwwpptimeetingorg (on subscription)wwwieee-uffcorgmainpublicationsfcsindexasp (on subscription)

European Time and Frequency Seminar (EFTS) ndash July 2014 in Besanccedilon (F)

NIST Time amp Frequency Seminar ndash June 2014 in Boulder (CO USA)

CUSO doctoral school on atomic clocks (2010 2012 amp 2014)

ESSENTIAL BIBLIOGRAPHY

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 52Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

Tower clocks (1300)verge-and-foliot mechanism

Precision Stabilityin seconds

per day

1 ns

1 s

100 ps

10 s

1000 s

Huygens Pendulum (1650)pendulum

Marine chronometers

(1750) Harrison

1 ms

Atomic clocks (1950)

Hydrogen Maser

Caesium beam Rubidium clock

Quartz oscillators

(1930)

1 s

Earth rotation

10 ns

10 ps

The metamorphosis oftime measurement

-3000 -1500 -170 800 1300 1600 19001700 2000

Marine chronometers Space atomic clocks

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf

13th PSI Summer SchoolZug August 9-15 2014 53Atomic clocks basic principles applications and current trends

Gaetano Mileti UniNe 10082014

THANK YOU FOR YOUR ATTENTION Prof Gaetano MiletiLaboratoire Temps ndash Freacutequence (LTF)Av Bellevaux -51Universiteacute de NeuchacirctelCH-2000 NeuchacirctelSwitzerland

Gaetanomiletiuninechwwwuninechltf