Formation of polarization-squeezed states of light in spatially periodic nonlinear-optical media

A new possibility for generating a nonclassical state of a vector electromagnetic field is considered. It is shown that polarization-squeezed light, in which the quantum fluctuations of one of the Stokes parameters characterizing the polarization properties of the light are smaller than in the coherent state, can form as a result of a nonlinear interaction between two waves with orthogonal polarizations in a spatially periodic medium. The region of uncertainty of the polarization state for coherent light in the space of the Stokes parameters is a sphere, and the region for polarization-squeezed light is an ellipsoid. A definite analogy between suppression of the quantum fluctuations of the Stokes parameters of polarization-squeezed light and the components of quadrature-squeezed light is traced. The optimal conditions for obtaining polarizationsqueezed light with respect to the parameters of the problem are elucidated. It is shown, in particular, that the relationship between the phases of the original waves at the entrance to the nonlinear medium and the linear coupling coefficient of the waves are of great importance here. O 1995 American Institute of Physics.