Model of Orthogonal Two-Wave Mixing in Optically Active Photorefractive Crystal of Cubic Symmetry

We presented a complete physical model describing the process of two-wave vectorial mixing in optically active photorefractive crystals of cubic symmetry for an orthogonal interferometer scheme. Using the model, we calculated the two-wave interaction in a gyrotropic photorefractive crystal of bismuth titanate B₁₂TiO₂₀ at two wavelengths of 633 and 532 nm. Studies using the complete model showed that the full polarization independence mode is not achieved. It was found that it is possible to select the parameters of the crystal and interacting waves for the quasi-polarization independence mode, when signal changes caused by polarization instability of the signal wave are reduced to a minimum (no more than 6%). Based on the obtained results, it is recommended to choose a PRC with a high optical activity value for the implementation of polarization-independent interferometric schemes.