Analysis and calculation on photorefractive property of Fe:LiNbO_3 crystal

The photorefractive properties of Fe:LiNbO 3 crystal depend on two factors. The one is the technique conditions and parameters for preparing of the photorefractive crystals , the other is close related with the recording optical geometry and the C axis direction of crystal. A set of formula of index modularity of photorefractive crystal in the always used 90° recording geometry is derived. The relationship of polarization of writing beams, the axis direction of crystal, and index modularity of volume holograms is analyzed.