NONLINEAR VECTORIAL DEGENERATE 4-WAVE-MIXING IN ISOTROPIC SATURABLE GAIN-MEDIA

The polarization dependence of degenerate four-wave mixing for isotrop ic saturable gain media is theoretically and numerically studied. The weak-probe limit is no longer needed in our model for developing nonli near vectorial coupled-wave equations for the interacting beams. Discr epancy between the two models is presented. It is found that, by compa rison with our model, the weak-probe-limit model is no longer valid wh en the fluence of the pump beams approaches the saturation fluence of the material or the fluence of the probe beam exceeds one-tenth that o f the pump beams. The results also show that switching occurs between the transmission and reflection gratings when the forward pump fluence is changed.