Can optical squeezing be generated via polarization self-rotation in a   thermal vapour cell?
  The traversal of an elliptically polarized optical field through a thermal vapour cell can give rise to a rotation of its polarization axis. This process, known as polarization self-rotation (PSR), has been suggested as a mechanism for producing squeezed light at atomic transition wavelengths. In this paper, we show results of the characterization of PSR in isotopically enhanced Rubidium-87 cells, performed in two independent laboratories. We observed that, contrary to earlier work, the presence of atomic noise in the thermal vapour overwhelms the observation of squeezing. We present a theory that contains atomic noise terms and show that a null result in squeezing is consistent with this theory. 
M.T.L. Hsu, A. Dantan, J. Cviklinski, A. Bramati, G. Hetet, A. Peng,   C.C. Harb, H.-A. Bachor, M.T. Johnsson, J.J. Hope, M....