Analysis of output beam polarization in higher-order self diffraction via two-wave mixing in BSO crystal

Generation of two higher-order diffraction beams in two-wave mixing in transmission geometry have been analyzed theoretically in photorefractive cubic crystal of 23 symmetry, BSO (Bismuth Silicon Oxide) and considering its optical activity as one of the important parameter. Results are shown graphically by solving coupled wave equations using fourth-order Runge–Kutta method. The effect of polarization state of pump beam, optical activity, off-Bragg parameter, coupling coefficients, absorption and thickness of crystal has been analyzed on the beam intensities and their respective polarizations. It has been observed that as the value of the off-Bragg parameter reduces the transfer of energy to the higher-order beams increases. It has been also observed that by selecting proper input beam polarization and crystal thickness, diffracted beam intensity and its polarization could be controlled considerably. It has also been seen that by controlling input pump beam polarization, particular higher-order beam can be selectively amplified.