Relative-intensity squeezing from

FOUR-Wave Mixing in Rubidium vapor


Raphael Pooser, Alberto M. Marino, 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 and entanglement 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 verified the presence of entanglement between these multi-mode beams by analyzing the intensity difference and the phase sum noise with a dual homodyne detection and measuring more than 4 dB of squeezing in both cases. This amount of squeezing also implies EPR correlations between the probe and the conjugate. The multi-spatial-mode character of the entanglement is shown by using an arbitrarily shaped local oscillator.


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.† We have built a compact source of squeezed beams for use in such experiments. One of the goals of this experiment is the generation of a correlated atom laser by transferring the quantum correlations of the photons to an ensemble of cold atoms.


Name: Raphael Pooser

Mentorís name: Paul D. Lett

Division: 842

Laboratory: Physics

Room and Building: B241/bldg216

Mail Stop: 8424

Telephone #:  (301) 975-2353

FAX #: (301) 975-8272


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