RESUMEN
We report phase-sensitive amplification (PSA) of a near-infrared electromagnetic field using room-temperature 85Rb atoms possessing ground-state coherence. Our novelty is in achieving significant optical PSA by manipulating the intensity and phase of a frequency-separated microwave field. PSA is obtained by inducing a three-wave mixing nonlinear process utilising a three-level cyclic scheme in the D1 manifold. We achieve a near-ideal PSA with a gain of 7 dB over a range of 500 kHz bandwidth with very low pump-field intensities and with low optical depths. Such a hybrid, ground-state-coherence-assisted PSA is the first such demonstration using atomic ensembles.
RESUMEN
We experimentally observe coherent generation of a near-infrared optical field through a three-wave mixing phenomenon in an atomic energy level scheme of Rb85 atoms. This nonlinear generation process in a centro-symmetric thermally broadened atomic system is made possible through a novel interaction between induced electric and magnetic dipoles. The two-photon and three-photon coherence present in our scheme eliminates excited state decoherence. Thus, our scheme represents a minimal optical decoherence scheme which could be used to transfer quantum states between microwave-to-optical frequency regimes with near-unit fidelity.