Generation of squeezed vacuum with hot and ultra-cold Rb atoms

Transcription

1 Generation of squeezed vacuum with hot and ultra-cold Rb atoms Eugeniy E. Mikhailov, Travis Horrom, Irina Novikova Salim Balik 2, Arturo Lezama 3, Mark Havey 2 The College of William & Mary, USA 2 Old Dominion University, USA 3 Instituto de Física, Uruguay January 5, 2 PQE Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 / 9

2 People Left to right: Arturo Lezama, Eugeniy Mikhailov, Mark Havey, Salim Balik, Travis Horrom, and Irina Novikova Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 2 / 9

3 Heisenberg uncertainty principle Optics equivalent φ N The more precisely the PHASE is determined, the less precisely the AMPLITUDE is known, and vice versa Optics equivalent strict definition X 2 X 2 2 X = a + a 2 X 2 = a a 2i Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 3 / 9

4 Coherent states of light unsqueezed amplitude-squeezed phase-squeezed angle-squeezed Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 4 / 9

5 Quantum memory with atomic ensembles Probe transparency dependence on its detuning. a Transparency [Arb. Unit] ω p Probe detuning [Arb. Unit] c b ω bc Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 5 / 9

6 Quantum memory with atomic ensembles Probe transparency dependence on its detuning. a Probe transparency dependence on its detuning. Transparency [Arb. Unit] ω p ω d Transparency [Arb. Unit] Probe detuning [Arb. Unit] b ω bc c Probe detuning [Arb. Unit] Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 5 / 9

7 Quantum memory with atomic ensembles Probe transparency dependence on its detuning. a Probe transparency dependence on its detuning. Transparency [Arb. Unit] ω p ω d Transparency [Arb. Unit] Probe detuning [Arb. Unit] Storage and retrieval b ω bc c Probe detuning [Arb. Unit] Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 5 / 9

8 Quantum memory with atomic ensembles Probe transparency dependence on its detuning. a Probe transparency dependence on its detuning. Transparency [Arb. Unit] ω p ω d Transparency [Arb. Unit] Probe detuning [Arb. Unit] Storage and retrieval single photon b ω bc c Probe detuning [Arb. Unit] Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 5 / 9

9 Quantum memory with atomic ensembles Probe transparency dependence on its detuning. a Probe transparency dependence on its detuning. Transparency [Arb. Unit] ω p ω d Transparency [Arb. Unit] c Probe detuning [Arb. Unit] Probe detuning [Arb. Unit] b ω bc Storage and retrieval single photon squeezed state (Furusawa and Lvovsky PRL 28) Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 5 / 9

10 Quantum memory with atomic ensembles Probe transparency dependence on its detuning. a Probe transparency dependence on its detuning. Transparency [Arb. Unit] ω p ω d Transparency [Arb. Unit] c Probe detuning [Arb. Unit] Probe detuning [Arb. Unit] b ω bc Storage and retrieval single photon squeezed state (Furusawa and Lvovsky PRL 28) Squeezed state requirements for a quantum memory probe Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 5 / 9

11 Quantum memory with atomic ensembles Probe transparency dependence on its detuning. a Probe transparency dependence on its detuning. Transparency [Arb. Unit] ω p ω d Transparency [Arb. Unit] Probe detuning [Arb. Unit] Storage and retrieval single photon b squeezed state (Furusawa and Lvovsky PRL 28) Squeezed state requirements for a quantum memory probe ω bc c Probe detuning [Arb. Unit] squeezing carrier at atomic wavelength (78nm, 795nm) squeezing within narrow resonance window at frequencies(<khz) Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 5 / 9

12 Quantum memory with atomic ensembles Probe transparency dependence on its detuning. a Probe transparency dependence on its detuning. Transparency [Arb. Unit] ω p ω d Transparency [Arb. Unit] Probe detuning [Arb. Unit] Storage and retrieval single photon b squeezed state (Furusawa and Lvovsky PRL 28) Squeezed state requirements for a quantum memory probe ω bc c Probe detuning [Arb. Unit] squeezing carrier at atomic wavelength (78nm, 795nm) squeezing within narrow resonance window at frequencies(<khz) Traditional nonlinear crystal based squeezers are capable of it, but they are extremely technically challenging especially at short wave length. Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 5 / 9

13 Self-rotation of elliptical polarization in atomic medium SR Ω + Ω - A.B. Matsko et al., PRA 66, 4385 (22): theoretically prediction of 4-6 db noise suppression a out = a in + igl 2 (a in a in) () Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 6 / 9

14 Will something so simple work? Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 7 / 9

15 Will something so simple work? Yes! J. Ries, B. Brezger, and A. I. Lvovsky, Experimental vacuum squeezing in rubidium vapor via self-rotation, PRA 68, 258 (23). Observed.85dB of squeezing at bandwidth 5-MHz Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 7 / 9

16 Will something so simple work? Yes! J. Ries, B. Brezger, and A. I. Lvovsky, Experimental vacuum squeezing in rubidium vapor via self-rotation, PRA 68, 258 (23). Observed.85dB of squeezing at bandwidth 5-MHz No! M. T. L. Hsu et al., Effect of atomic noise on optical squeezing via polarization self-rotation in a thermal vapor cell, PRA 73, 2386 (26). Observed 6dB of excess noise after the cell Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 7 / 9

17 Will something so simple work? Yes! J. Ries, B. Brezger, and A. I. Lvovsky, Experimental vacuum squeezing in rubidium vapor via self-rotation, PRA 68, 258 (23). Observed.85dB of squeezing at bandwidth 5-MHz No! M. T. L. Hsu et al., Effect of atomic noise on optical squeezing via polarization self-rotation in a thermal vapor cell, PRA 73, 2386 (26). Observed 6dB of excess noise after the cell Possible. A. Lezama et al., PRA 77, 386 (28). Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 7 / 9

18 Will something so simple work? Yes! J. Ries, B. Brezger, and A. I. Lvovsky, Experimental vacuum squeezing in rubidium vapor via self-rotation, PRA 68, 258 (23). Observed.85dB of squeezing at bandwidth 5-MHz No! M. T. L. Hsu et al., Effect of atomic noise on optical squeezing via polarization self-rotation in a thermal vapor cell, PRA 73, 2386 (26). Observed 6dB of excess noise after the cell Possible. A. Lezama et al., PRA 77, 386 (28). Definitely Eugeniy E. Mikhailov et al. Optics Letters, Issue, 33, 23-25, (28). Definitely Eugeniy E. Mikhailov et al. JMO, Issues 8&9, 56, , (29). Definitely Philippe Grangier et al. Optics Express, 8, Issue 5, pp (2).4 db of squeezing Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 7 / 9

19 Setup V.Sq LO PBS 87 RB PBS Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 8 / 9

20 Noise contrast vs detuning in hot 87 Rb vacuum cell Noise (db) Noise (db) F g = 2 F e =, 2 Noise vs detuning Transmission Frequency (GHz) PSR noise Noise vs quadrature angle Quadrature angle (Arb.Units) Noise (db) Noise (db) F g = F e =, 2 Noise vs detuning Transmission Frequency (GHz) PSR noise Noise vs quadrature angle Quadrature angle (Arb.Units) Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 9 / 9

21 Squeezing vs detuning in 87 Rb at 795 nm 87 Rb cell + 2.5Torr Ne (a) P=. mw, (b) P=.5 mw, (c) P=4.2 mw, (d) P=6.6 mw Self-rotation angle (rad) (b) (c) (a) (d) (I) Transmission Noise power (db) (d) (c) (b) (a) F g =2, F e = F g =2, F e = Frequency (GHz) (II) F g =, F e = F g =, F e =2 (III) Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 / 9

22 Low frequency squeezing vs noise sidebands frequency in 87 Rb at 795 nm 87 Rb cell + 2.5Torr Ne, T=63.3 C (a) P=. mw, (b) P=.5 mw, (c) P=4.2 mw, (d) P=6.6 mw -. (I) Noise power (db) (a) (b) (d) (c) Frequency (khz) Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 / 9

23 Low frequency squeezing vs noise sidebands frequency in 87 Rb at 795 nm 87 Rb cell + 2.5Torr Ne, T=63.3 C P=.5 mw Noise power (db) Frequency (khz) (II) Eugeniy E. Mikhailov, Irina Novikova: Optics Letters, Issue, 33, 23-25, (28). Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 2 / 9

24 Low frequency squeezing vs noise sidebands frequency in 87 Rb at 795 nm 87 Rb cell + 5Torr Ne, T=63.3 C P=.5 mw Noise (dbm) Frequency (khz) Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 3 / 9

25 Excess noise and the source of the controversy No buffer gas near F g = 2 F e = 2 transition Squeezing at detuning 2 vs temperature and power Power, mw Temerature,C -.5 Squeezing occurs in the rather narrow parameters space Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 4 / 9

26 MOT squeezer T = 2 µk, N = 2 /cm 3, OD = 5, beam size =. mm V.Sq LO PBS PBS Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 5 / 9

27 Noise contrast in MOT with 87 Rb F g = 2 F e = Noise (db) Quadrature angle (Arb. Units) Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 6 / 9

28 Squeezing in MOT with 87 Rb F g = 2 F e =.2..8 Noise (db) Quadrature angle (Arb. Units) Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 7 / 9

29 Theoretical prediction for MOT squeezing with 87 Rb F g = 2 F e =, 2 high optical density is very important γ = - Γ 87 Rb D Rabi = 3 Γ squeezing antisqueezing 2 6 γ = -2 Γ F=2 to F'= F=2 to F'=2-8 F=2 to F'= F=2 to F'=2 Normalized noise power (db) γ = -3 Γ Optical density: γ = -4 Γ -8 F=2 to F'= F=2 to F'=2-8 F=2 to F'= F=2 to F'= Laser detuning (MHz) Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 8 / 9

30 Summary Self-rotation based squeezing is possible in hot and ultra-cold 87 Rb vapor Squeezing is generated in the range from khz to several MHz Such vacuum squeezing is suitable for atomic quantum memory tests Advantages of the PSR squeezing Requires very little optical power (< mw) Generated at atomic transition wavelength Potentially can be generated at any wavelength where the suitable transition exists think blue or even ultraviolet Eugeniy Mikhailov (W&M) Squeezing with Rb vapor PQE 2 9 / 9