A Model of Optical Bistability and Polarisation Evolution in Birefringent χ$\text{}^{(2)}$ Nonlinear Media

We present a model calculation of optical bistability and polarisation evolution in optically birefringent media based on the interaction of three waves. Second-order optical nonlinearity (described by the third rank susceptibility tensor) is assumed to be dominant. A bistable light transmission is analysed in terms of standard Fabry-Perot model of feedback, and is a direct consequence of the results obtained for a semi-infinite medium. A second effect considered in the paper is evolution of polarisation state of the waves involved in these processes. We derived a closed formula for intensity-dependent refractive index, which corresponds to that used in the case of third-order nonlinear media. As a result, we calculated both intensity and Stokes parameters of transmitted light.