Document Abstract
Phase-conjugate (PC) reflectivity is one of the most important parameters that characterize the four-wave
mixing process in photorefractive (PR) materials. In this paper, the effect of the crystal thickness, modulation ratio and
pump intensity ratio on the PC reflectivity of four-wave has been studied in case of the degenerate four-wave mixing
process in PR materials. Also, the influence of photoconductivity and dielectric constant of PR materials on the PC
reflectivity of the four-wave has been analyzed in case of the non-degenerate wave mixing process of PR materials. It has
been found that the reflectivity of the PC wave for BGO and BSO have shown almost similar behavior like LiNbO3 with
the peak values observed at 1.21 pS/cm and 1.69 pS/cm. The present results showed that the reflectivity of the PC wave is
different for all the materials of dielectric constant 32 (LiNbO3), 40 (BGO) and 56 (BSO) and is higher for higher value of
dielectric constant, suggesting that the reflectivity of the PC wave not only depends on the dielectric constant of the
photorefractive materials but also strongly depends upon the photoconductivity of the materials. For lower value of
coupling coefficient, it is observed that the peak intensity of reflectivity of PC wave occur at higher thickness and for higher
values of coupling coefficient it is observed at lower crystal thickness. The enhancement in the reflectivity of the optical
phase-conjugate wave would greatly improve the performance of the devices based on the four wave mixing process. Such
devices find applications in the areas like optical memories, information processing, real-time processing, beam steering,
beam combining, resonators and pattern formation.