Theoretical Studies of Nonlinear Optical Effects in Photorefractive Materials

Abstract

The present thesis titled Theoretical Studies of Nonlinear Optical Effects in newlinePhotorefractive Materials is a study on the two wave-mixing in photorefractive materials, newlineand its application for coupled cavity ring resonators. The photorefractive effect was newlinediscovered after the invention of lasers. In 1966, Ashkin, Boyd and their co-workers at Bell newlineTelephone Laboratory during their study on optically-induced refractive index newlineinhomogeneities in crystals of lithium niobate (LiNbO3) found that the material s optical newlineproperty (refractive index) changed by the spatial variation of the intensity of light. These newlinematerials are called photorefractive materials and the effect is known as photorefractive newlineeffect. This effect is believed to arise from the optically generated charge carriers which newlinemigrate when the crystal is exposed to a spatially varying pattern of illumination with newlinephotons having sufficient energy. Migration of the charge carriers due to drift and diffusion newlineproduces a space charge separation which gives rise to space charge field. Such a field newlineinduces a refractive index change via Pockels effect. newline