Polariton squeezing in semiconductor microcavities

Measurements on the light going out of the cavity, i.e. the photon part of the polariton field are reported. Squeezing of the polariton field is then deduced. From the calculations made, the best squeezing rate is expected in the vicinity of a bistability turning point. The sample used in these experiments is a high finesse GaAs microcavity containing one InGaAs quantum well with low indium content, with a small angle between the two mirrors. The light source is a single-mode tunable cw Ti:sapphire laser with a linewidth of the order of 1 MHz. The laser beam is power-stabilized using an electro-optic modulator and spatially filtered by a 2 m-long single mode fiber. Noise measurement is achieved by homodyne detection. From the squeezing measured outside the cavity, a 9% squeezing of the polariton field is inferred. This result opens the way to the generation of nonclassical states of light and matter in semiconductor microcavities.