OPTICAL BISTABILITY AND MULTISTABILITY IN THE LINEAR PHOTOREFRACTIVE OSCILLATOR ACCOMPANIED BY A FREQUENCY-SHIFT DUE TO GRATING MOTION

We investigate the bistable and multistable response of the phase conjugate reflectivity (PCR) for the case of a linear photorefractive (PR) oscillator in presence of the moving grating operation. Numerical evaluation of stable multiple solutions of the PCR shows enhancement, bistable, multistable and self-oscillating behaviours with respect to the control parameters like the frequency-shift (OMEGA) due to grating motion, reflectivities (M1 and M2) of cavity mirrors, the coupling strength (of complex gL and real g0L values) and the PR phase shift (phi(PR)). If the different branches are assumed to be stable, multistable but isolated branching behaviour with an increased PCR can be predicted. Results are interpreted physically by considering the competitions between (i) the strengths of two moving transmission gratings that arise from A1-A4 (forward oscillating pump-incident) and A2-A3 (backward oscillating pump-phase conjugate) interferences and (ii) the applied frequency detuning that causes the gratings to move and the self-induced cavity detuning that appears when the gratings are stationary. Numerical evidence of the results is presented graphically.