Interaction of two polarization modes in a spatio-periodic nonlinear medium: Generation of polarization-squeezed light and quantum non-demolition measurements of the Stokes parameters

The possibility of formation of polarization-squeezed light in the case of the interaction of two orthogonally polarized waves in a spatio-periodically Kerr-like medium is considered. In such a quantum polarization state of light the fluctuations of one of the Stokes parameters are less than in the coherent one. Both linear and nonlinear energy exchange between polarized modes are very important for the formation of the non-classically polarized light. For the first time we offer and analyse the procedure of the quantum non-demolition measurement (QND) of the Stokes parameters of light. Conditions of realization of the QND measurement are formulated in the general case.