Relative-intensity squeezing from

FOUR-Wave Mixing in Rubidium vapor

Alberto M. Marino, Colin F. McCormick, Vincent Boyer, and Paul D. Lett

Category: Physics

     The initial interest in squeezed states was stimulated by the possibility of increasing the sensitivity of interferometers for applications such as gravitational wave detection. In recent years the interest has shifted to the quantum correlations present in multi-mode squeezed fields, which have applications in quantum information and quantum computing.  We study the use of a nondegenerate four-wave mixing process in a rubidium vapor at 795 nm to generate such correlations.  The scheme is based on a double lambda system, which makes it possible to reduce the limiting effects of losses and spontaneous emission. 

     We have been able to obtain over 6 dB of relative-intensity squeezing and we have measured squeezing at detection frequencies below 10 kHz.  As a result of the four-wave mixing process and propagation through the vapor cell, the probe and conjugate beams exit the cell with a relative time delay.  We are currently studying the effect of this delay on the squeezing spectrum and the measured correlations.

     One of the advantages of this scheme for the generation of correlated photons is that it produces narrowband photons near an atomic resonance.  This makes this source ideal for experiments involving cold atoms or atomic ensembles.  Among the different applications for this quantum state of light are quantum imaging and the generation of a correlated atom laser by transferring the quantum correlations of the photons to an ensemble of cold atoms.

Name: Alberto M. Marino

Mentor’s name: Paul D. Lett

Division: 842

Laboratory: Physics

Room and Building: B247/bldg216

Mail Stop: 8424

Telephone #:  (301) 975-8885

FAX #: (301) 975-8272

Email: alberto.marino@nist.gov

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