Parra - Ultrashort Pulse (USP) Laser Matter Interactions - Spring Review 2012
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Transcript of Parra - Ultrashort Pulse (USP) Laser Matter Interactions - Spring Review 2012
1 DISTRIBUTION A: Approved for public release; distribution is unlimited. 15 February 2012
Integrity Service Excellence
Riq Parra
Program Manager
AFOSR/RSE
Air Force Research Laboratory
Ultrashort Pulse (USP)
Laser-Matter
Interactions
08 MAR 2012
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USP Laser Matter Interactions
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Characteristics of short pulse lasers
• The program aims to understand and control light sources exhibiting
extreme bandwidth, peak power and temporal characteristics.
• Portfolio sub-areas: optical frequency combs, high-field science,
attosecond physics.
Peak
Power
Pulsewidth Bandwidth
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USP
Lasers
Secondary Radiation Sources generation of particle & photons
• High power THz generation
• Extreme ultraviolet
lithography
• Biological soft x-ray
microscopy
• Non-destructive evaluation
• Medical imaging/therapy
Metrology stabilized, ultra-wide bandwidth
• Ultra-stable freq sources
• Arb waveform generation
• High precision spectroscopy
• Frequency/time transfer
• Ultra-wideband comms
• Coherent LIDAR
• Optical clocks
• Calibration
Material Science ultrashort, high peak power
• Surgery
• Chemical analysis (LIBS)
• Surface property
modification
• Non-equilibrium ablation
• Micromachining
• Ultrafast photochemistry
• Attochemistry
Propagation in media self-channeling
• Remote sensing
• Remote tagging
• Directed energy
• Electronic warfare
• Countermeasures
• Advanced sonar
Particle Acceleration ultrahigh electric field gradients
• Table-top GeV electron
accelerators
• MeV ion sources for
imaging
• Isotope production
• Hadron tumor therapy
• Proton-based fast
ignition
Applications of USP Lasers
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Modelocked femtosecond lasers
Source: Diddams, JOSA B (2010)
Thorlabs
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Mode-locked lasers as broadband phase-
coherent optical sources (optical
frequency combs)
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PI: James Gord, AFRL/RZ
Advancing Ultrafast Lasers for High-
Bandwidth 4D Metrology
• Ultrashort pulses for propulsion measurements
• Ultrafast laser–based spectroscopic techniques for investigating the physics
and chemistry of reacting flows.
• Generate top-quality data for
• advanced concept development and model validation (R&D)
• propulsion-system performance assessment (T&E)
• weapon-system active combustion control (ACC)
• Measure everything, everywhere, all the time…
Pratt & Whitney F119
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PI: James Gord, AFRL/RZ
Spectrally Resolved Femtosecond
CARS 1D Line Imaging
Key fs-CARS advantages
• >3 OOM faster data acquisition
• 1D line vs. point measurements
• Free from collisional broadening
• Nonresonant-background control
• Strong coherences
• Improved accuracy, precision
• Species-selective [n] and T
• Multiple-species excitation
16-shot avg.
Single-shot
Single-shot, one-dimensional thermometry in flames
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An optical frequency comb
Source: Diddams, JOSA B (2010)
Repetition rate
phase-locked to a
microwave reference.
fo measured via the
heterodyne between
the second harmonic
of the IR & VIS comb
components.
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Metrological applications
of optical frequency combs
Source: Newbury, Nature Photonics (2011)
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Microresonator frequency combs
Source: Kippenberg et al., Science (2011)
CaF2 SiN rings Silica toroids
FY2012 Basic Research Initiative (BAA-AFOSR-2012-02)
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Mode-locked lasers as high peak power
sources (high field science)
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Progress in peak intensity
• Over the last two decades, a 6 order of magnitude increase in achieved
focused intensities in table-top systems.
Source: CUOS website
2x1022
Phenomena Relevance
Thomson scattering Gamma rays source
Laser wakefield
acceleration
Compact e-
accelerators
Particle and x-ray
emission from solids
Proton & x-ray
sources
High harmonic
generation
Coherent EUV
sources
Filamentation Propagation of
EM pulses
Laser ablation
of solids
Laser machining
& patterning
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High intensity lasers are reducing from
national lab to university scale systems
Attributes LLNL Petawatt (1998) Thales Alpha 10 (2012)
Power per pulse 660 J 40 J
Pulse width 440 fs 25 fs
Focused intensity 7 x 1020 (W/cm2) n/a
Peak power 1.5 PW 1.3 PW
Size Building 14 x 19 ft2
Rep rate few shots/day 1 Hz
Gain material Nd:glass Ti:Sapphire
Commercial product!
SIZE Thales
Alpha 10
brochure
Thales Alpha 10
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Laser micromachining & patterning
• Ultrashort laser pulses open up novel
possibilities and mechanisms for laser-solid
interactions.
• Demonstrated femtosecond laser processing
and surface texturing techniques to engineer
surface structures & properties (e.g. darkened &
colored metals, super wicking surfaces).
• Studied nanostructure-covered laser-induced
periodic surface structures (NC-LIPSS) &
nanostructure-covered large scale waves (NC-
LSW).
Colorizing metals using femtosecond lasers
Super wicking surfaces: Array of parallel
microgrooves generates strong capillary force.
PI: Chunlei Guo, U of Rochester
NC-LIPSS NC-LSW
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Propagation of high-intensity USPL pulses
• Propagation of localized high-intensity laser pulses is of
interest for remote sensing, imaging, communications and
remote interactions.
• Such propagation in air leads to self-channeling (i.e.
filaments) and plasma formation.
• AFRL/RDLA Filamentation Team is engaged in an
experimental, theoretical and computational effort to:
• Develop computational models for long-distance fs propagation
as an extended free space waveguide.
• Study filament propagation for long distances (2, 5 & 7 km test
sites available).
• Characterize fs-laser filament physics necessary for
coupling/confining external EM-Fields.
• Understand filamentation induced electrical shorting.
PI: William P Roach, AFRL/RD
9-inch filament bundle propagation
through kV-level E-Field
Range
High-performance
GPU computing
enclave
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PI: Pavel Polynkin, Arizona
Optical breakdown of air triggered by
femtosecond laser filaments
• Generation and 200x enhancement of dense
plasma channels at range via dual-pulse
femtosecond-nanosecond laser excitation.
• Control of femtosecond laser filamentation
through laser beam engineering. Extended bottle-
like plasma-channel distributions using vortex
beams and high order Bessel beams.
100 laser shots
fs pulse only
Single shot
fs + ns pulses
Bottle-like filament
patterns produced by
vortex beams in water
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High Harmonic Generation (HHG)
Microscopic single-
atom physics of HHG
Macroscopic phase-matched
harmonic emission
Source: Popmintchev et al., Nat Photonics (2010),
Popmintchev et al., CLEO postdeadline (2011)
Co Ni Cu Fe C O N B
lLASER=3.9 mm
0.8mm
2mm
WATER WINDOW
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Direct Frequency Comb Spectroscopy
in the Extreme Ultraviolet
• Generating frequency combs in the extreme
ultraviolet (XUV) via high harmonic generation
(HHG) in a femtosecond enhancement cavity.
• Demonstrated generation of >200 µW per
harmonic down to 50 nm.
• Ultrahigh precision spectroscopy below the
100 nm spectral region:
• Direct frequency comb spectroscopy of Argon
transition at 82 nm with resolved 10 MHz
linewidth (atomic thermal motion limited).
10 MHz Ar @ 82 nm
PI: Jun Ye, U of Colorado
119 nm 97 nm 82 nm 47 nm 71 nm
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Diocles 100 TW laser system
• Nd:YAG pumped Ti:Sapphire
• 3.5 J in < 30 fs, 100 TW @ 10 Hz
Spot size (FWHM) = 16 microns
Enclosed energy > 75-80 %
Focal spot
PI: Donald Umstadter, U of Nebraska
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• Scattering from a 300 MeV electron beam
can Doppler shift a 1-eV energy laser
photon to 1.5 MeV energy.
• Demonstrated > 710 MeV electron beams
with no detectable low-energy
background.
• Proof-of-principle experiments are
underway.
Laser-driven x-rays generation
(0.1 – 10 MeV) PI: Donald Umstadter, U of Nebraska
Super
Sonic
Nozzle
E-Beam
Scattering
Laser Pulse
Experimental geometry
for generating x-rays via
Thomson scattering
> 710 MeV
electrons
Energy tunability from 0.1 – 0.8 GeV.
Monoenergetic: ΔE/E ~ 10 %
Low angular divergence: 1-5 mrad
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Repetitive petawatt-class laser
• Completed upgrade to 0.7 PW
@ 0.1 Hz.
10-cm Ti:Sapphire power amplifier
25-J Nd:glass pump lasers
New gratings for pulse compressor
PW Specifications
Wavelength 805 nm
Pulse duration < 30 fs
Rep rate 0.1 Hz
Pulse energy 20 J
Peak power 0.7 PW
Strehl ratio 0.95
Max intensity (f/2) 1x1023 W cm-2
PI: Donald Umstadter, U of Nebraska
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Mode-locked lasers as sources of
ultrashort EM pulses (attosecond physics)
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Generation of single attosecond
photon pulses
Source: Corkum, Nature Physics (2007),
Goulielmakis, Science (2008)
Streaking spectrogram Retrieved intensity profile
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Attosecond pulses provide a new set
of metrology tools
Source: Krausz, RMP (2009)
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Sub-cycle optical pulses for isolated
attosecond pulse generation
• Coherent wavelength multiplexing of high
energy pulses, spanning two octaves, into
a non-sinusoidal waveform with sub-cycle
features.
• Shortest high-field transient lasts 0.8 cycles of the carrier frequency.
• Unique, scalable approach to higher
energies and rep rates for high average
power sources of isolated attosecond
pulses.
PI: Franz Kaertner, MIT High-energy optical
waveform synthesizer
Computed isolated attosecond pulse Synthesized waveform
0.8 cycles Waveform supports
directly isolated soft
X-ray pulse with
150 as duration (with
no gating).
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Optical frequency combs ultra-wide bandwidths
• Spectral coverage to exceed an
octave with high power/comb.
• Coherence across EUV-LWIR.
• Novel resonator designs (e.g.
micro-resonator based).
• Ultra-broadband pulse shaping.
• …
Attosecond science ultrashort pulsewidths
• Efficient, high-flux generation.
• Pump-probe methods.
• Probe atoms/molecules &
condensed matter systems.
• Attosecond pulse propagation.
• Novel attosecond experiments.
• Fundamental interpretations of
attosecond measurements.
• …
Summary and outlook
The program aims to understand
and control light sources exhibiting
extreme temporal, bandwidth and
peak power characteristics.
High-field laser physics high peak powers
• Laser-solid interactions.
• Fs propagation in media.
• Sources of secondary photons.
• Compact particle accelerators.
• High peak power laser
architectures.
• High repetition rates.
• New wavelengths of operation.
• …