Squeezing via two-photon transitions

Abstract

The squeezing spectrum for a cavity field mode interacting with an ensemble of three-level ‘‘Λ-configuration’’ atoms by an effective two-photon transition is calculated. The advantage of the three-level Λ system as a squeezing medium, that is, optical nonlinearity without atomic saturation, has recently been pointed out by Reid, Walls, and Dalton. We predict perfect squeezing at the turning points for dispersive optical bistability and good squeezing for a range of other cases. Three-level ladder atoms interacting by an effective two-photon transition are also shown to give perfect squeezing in the dispersive limit.