Polarization squeezing with cold atoms

Vincent Josse, Aurelien Dantan, Laurent Vernac, Alberto Bramati, Michel Pinard, Elisabeth Giacobino

Published 2003-04-03, updated 2003-05-12Version 2

We study the interaction of a nearly resonant linearly polarized laser beam with a cloud of cold cesium atoms in a high finesse optical cavity. We show theoretically and experimentally that the cross-Kerr effect due to the saturation of the optical transition produces quadrature squeezing on both the mean field and the orthogonally polarized vacuum mode. An interpretation of this vacuum squeezing as polarization squeezing is given and a method for measuring quantum Stokes parameters for weak beams via a local oscillator is developed.