RALI - Max Planck Societycryp10/Contributions/Adams_2010... · 2010-09-28 · (RALI) Near field Far...

Rydberg atomlight interaction: from nonlinear optics to quantum opticsMPIKS, Dresden.

September 14th 2010.

Rydberg atomlight interactions: from nonlinear optics to quantum optics

k¡1L < N¡1=3 < k¡1R




Rydberg AtomLight Interactions(RALI)





Escat /k2

r





Near field Far field





Near field Far field

k¡1L < N¡1=3 < k¡1R

Both




Black box

Input field Output field




Rydberg atoms


Can we exploit the extraordinary properties of Rydberg atoms to modify a light field in a useful way?



Applications I


Rydberg energy level detection

Electrometry Precision measurement

Coulomb's law at intermediate length scalesPlasma diagnostics

1. What does the output field tells us about the Rydberg atom or the environment of each Rydberg atom?

Rydberg constant

Surface interactions

Dipoledipole interactions

Coherent spectroscopy of the blockade



Applications II


Nonlinear optics Rydberg quantum optics (single photon nonlinear optics)

Quantum information

Production of technologically useful or interesting (nonclassical) light fields

Single photon source Strongly interacting photons Rydberg polaritons

Photon crystals Fractional quantum Hall states

Cavity QED (one atom at a time) Atomic ensembles

Haroche, Walther



What are the extraordinary properties of Rydberg atoms?: n scaling



Outline

1. Rydberg energy level detection

'Precision' measurement

2. Rydberg nonlinear optics

Giant Kerr effect

3. Effects dipole – dipole interactions on the optical response

Coherent spectroscopy of the blockade

4. Rydberg quantum optics



1. Rydberg atom detection



Detection via coherent atom light interactions

Weak excitation: single atom response

Â1 =i

V

d2ab²0~

1

°ab ¡ i¢

Twolevel

Â1 =i

V

d2ab²0~

1

° ¡ i¢

Multilevel



Mapping Rydberg character onto a strong optical transition

Dark state



Experimental setup



Typical spectra in a room temperature Rb vapour cell



'Precision measurement'



rf dressing and 'electrometry'

Bason et al. New J. Phys. 12, 065015 (2010)

26 MHz



Microwave dressing

5s – 5p – 46s 46p



Outlook: Microwave dressing

5s – 5p – 180s – 500s



2. Rydberg nonlinear optics: Kerr effect

¢n = k¢Âr



Âr = Â(1)r + Â(3)r E2

Âr = Â(1)r +

@Âr@!

¢!

Rydberg nonlinear optics: Kerr effect

¢n = k¢Ârng = 1 +

!

2

@Âr@!

Â(3) =(ng ¡ 1)®~!

¢! = ¡12

®E2~



Demonstration of giant Kerr effect in a thermal vapour cell



Electric field of a single oscillating dipole

Imaginary part

Real part Shift

Width

3. Dipoledipole interactions: electric field of another atom.



Semiclassical dipoledipole level shift and broadening



Why Rydberg?



Rydberg dark state

Rydberg fraction

µpc

¶2



Dipoledipole interactions: electric field of another atom.

Coupling Rabi frequency

Probe Rabi frequency



Tra n

s mis

sio n

Coherent spectroscopy of the blockade 5s – 5p 60s

1 pW



Experiment: low density (3 atom model)



Simple picture of suppression



Rydberg level shift / Broadening (high density)

Level shift

Broadening

Dephasing model



What might we learn from this data?

Shift is less than 500 kHz

Mean superatom spacing

8.0 microns

Dephasing of superatoms < 200 kHz

rb =

µC6~c

¶1=65.6 microns



Level shift due to a single quanta is larger than the line width.

4. Outlook: Experimental Rydberg quantum optics

Strong coupling

j2; a; aij0; b; bi

j1; a; bij0; a; bi

j0; a; aiV > ~



Single blockade volume

High optical depth per blockade

Single photon source

Single photon nonlinear optics

or a cavity

4. Outlook: Experimental Rydberg quantum optics



Single photon source directionality?

100 atoms randomly distributed in 3 x 1 micron

Pedersen and Molmer Phys. Rev. A, 79, 012320 (2009)

7 x 7 x 20 atoms

Olmos and Lesanovsky ring lattice



Single photon source directionality?

100 atoms randomly distributed in 3 x 1 micron

E(x; y; z) = E0w0weikze¡i®ei½

2=2Re¡½2=w2 ® = tan¡1

µ2z

kw20

¶



Gouy phase in the near field

Large effect in the near field but not so apparent in the far field

With Gouy phaseWithout Gouy phase



Summary

Rydberg nonlinear optics

Rydberg quantum optics

Rydberg atoms


Electrometry

Efield inside cells Efield close to surfaces

Spectroscopy of the blockade

Heidelberg

DurhamStuttgartDurham

Amsterdam



Acknowledgements

Jon Pritchard Kevin WeatherillAlex Gauguet(CNRS Toulouse)

Matt Jones Dan Maxwell

Theoretical support: Monsit Tanasittikosol, Robert Potvliege

Former members: Ashok Mohapatra (NISER, Bhubaneswar) Mark Bason (Pisa)

RALI - Max Planck Societycryp10/Contributions/Adams_2010... · 2010-09-28 · (RALI) Near field Far...

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