Intensity and Polarisation Bistability in Two Primary-Wave Mixing in Media with Second-Order Nonlinearity

In this paper we analyse theoretically the transmission of two strong laser beams through a medium exhibiting optical nonlinearity of the second order combined with a linear anisotropy. A standard model of two wave mixing was applied and closed formulas for intensity and polarisation state were obtained. Numerical calculations show that outgoing beams are very sensitive to the state of incoming beams and to the material characteristics. Under some realistic conditions we were able to obtain bistability of both intensity and polarisation state. The results also show how to modulate the intensity and polarisation state of one wave by another one.