Squeezed state experiments in sodium vapor
Mari W. Maeda, Prem Kumar, Jeffrey H. Shapiro
Squeezed states of light exhibit phase-sensitive quantum noise which falls below the semiclassical shot noise limit. We report results from experiments in sodium vapor to observe squeezed light. In a single-beam experiment, a dye laser beam transmitted through sodium vapor was homodyned. Phase-sensitive noise on the radio frequency offset modes was observed at or above the semiclassical limit.1 In a two-beam correlation experiment, the transmitted probe and the reflected conjugate beams in forward four-wave mixing were direct detected. Although this configuration does not generate squeezed light, the subtracted photocurrent exhibits subshot noise fluctuations.2 Phase-insensitive noise above the semiclassical limit was observed with a strong positive correlation between the probe and the conjugate photocurrents. In a squeezed state experiment, a probe-conjugate combination mode of forward four-wave mixing was homodyned.3 With the input beam blocked, the noise showed nonclassical phase-sensitivity with a minimum of 0.2 dB below the vacuum state limit. When only the probe or the conjugate beam was homodyned, the noise remained phase-insensitive near the vacuum state level.
Annual Meeting Optical Society of America•Jan 1, 1986•0 citations