Photorefractive Properties Varied With Li Composition in $\hbox {LiNbO}_{3}$ :Fe Crystals

LiNbO₃ : Fe crystals with different Li compositions were prepared in this paper. Both holographic storage and photo-induced light scattering experiments were carried out on these crystals. Our results showed that, with the increase of the Li composition in LiNbO₃ : Fe, the response time of the material was shortened largely, while the photoinduced light scattering in the crystals was suppressed significantly. These improvements of the photorefractive properties of LiNbO₃ : Fe were attributed to the change of polaronic system in the material. In addition, the rapid change of the photo-induced light scattering with the Li composition was found between 48.9 and 49.3 mol%. It was explained by the threshold effect of photo-induced light scattering with respect to the photovoltaic field.