Observation of quantum noise in the polarization of laser light in a rubidium-vapor cell

Experimental observation of quantum noise in the polarization of laser light that has passed through a dense Rb⁸⁷ atomic vapor is reported. The step-like noise spectrum is observed. Factors responsible for the form of the observed spectrum and the absence of noise “squeezing” predicted by Matsko et al. [Phys. Rev. A 63, 043814 (2001)] are discussed.