Funded by Hosted by

Phase shift of a weak coherent beam

by a single atom

Thanks to

Chen Zilong

Florian Huber

Lee Jianwei

Timothy Liew

Valerio Scarani

Syed Abdullah Aljunid, Gleb Maslennikov, Tey Meng Khoon,

Brenda Chng, Christian Kurtsiefer

Brief Outline

• Motivation for the experiment

• Theoretical description

• Experiment and Results

Motivation

• Quantify interaction of a two-level atom with

light

• Strong interaction without a cavity.

Tey M.K. et al. Nature Physics 4, 924 - 927 (Dec 2008)

Scattering Ratio

in

scatscat

P

PR

Quantifying Interaction

Pscat

PscatPscat

Pscat

Pin

Scattering Ratio

Transmission

Phase shift

2

in

2

out EET

)arg( inout

EE

in

scatscat

P

PR

Quantifying Interaction

2

outE2

inE

Weak excitation, and on-resonant input light

Atom-Light Interaction

scatinout EEE

Weak excitation, and on-resonant input light

Atom-Light Interaction

i

iRE

221 scat

in(On axis)‏natural linewidth

detuning

scatinout EEE

Strong Interaction

G. Zumofen, et. al.,

Phys. Rev. Lett. 101, 180404 (2008)‏

M. K. Tey, et. al.

New J. Phys. 11 (2009) 043011

CClosed expression for focused

Gaussian beam

Strong Interaction

G. Zumofen, et. al.,

Phys. Rev. Lett. 101, 180404 (2008)‏

M. K. Tey, et. al.

New J. Phys. 11 (2009) 043011

CClosed expression for focused

Gaussian beam

0.84

2.30.16

Experimental Setup

Experimental Setup

Experimental Setup

Experimental Setup

Experimental Setup

Experimental Setup

Experimental Setup

Experimental Setup

probe2.5 cm

Phase Measurement

Mach-Zehnder interferometer.

dc

dc

PP

PParccos

1~~

2

~~

arccos'

''

''

dc

dc

II

IIc

d

Phase Measurement

Mach-Zehnder interferometer.

TPP

PP

dc

dc ''arccos'

dc

dc

PP

PParccos

'

1~~

2

~~

arccos'

''

''

dc

dc

II

IIc

d

1

)(2; ''

dc

dc

PP

PPT

Results

Transmission of

(93.9 ± 0.2)%

Max phase shift of

(0.9 ± 0.2) ° at‏~Γ/2

Rscat = 0.062 ± 0.003

= (8.6± 0.4)MHz

Theoretical

Transmission: 84%

max phase shift: 2.3°

22

2

scat22

2

in

2

out

4

214

R

E

ET

scatscat22

inout2

14arg)arg( iRR

EE

Conclusion

• Strong interaction of light with a single atom

can be observed by simple focusing.

• 0.9° phase shift of a weak coherent beam

observed together with 93.9% transmission.

Conclusion

• Strong interaction of light with a single atom

can be observed by simple focusing.

• 0.9° phase shift of a weak coherent beam

observed together with 93.9% transmission.

Thank You & The End

Antibunching in single atom fluorescence

Dipole trap laser wavelength: 980 nm

trapping

potential