LiNbO3中光折变全息的热固定特性

带输运模型方程和耦合波方程结合起来研究ＬｉＮｂＯ３晶体中体全息记录和热固定的特性。发现在一边记录一边固定时，同时存在的离子光栅通过减小耦合增益而影响了电子光栅的写入，且得到的固定后折射率光栅随深度的改变较小，这与记录完固定有非常大的区别，两种热固定方法得到的折射率光栅的衍射效率大小将主要决定于入射记录的实始光强比，该模型同时显示对于高掺杂浓度的ＬｉＮｂＯ３晶体的热固定，在其显影过程中，由于导带电子

Characters of Recording and Thermal Fixing in Lithium Niobate

A theoretical model, in which the band transport equations and the coupled wave equations are both considered, to describe the characters of recording and thermal fixing in LiNbO 3 is presented. It is found that in simultaneous fixing, the existing ionic grating affect the writing of the electronics grating by reducing the coupling gain and the grating envelope of the fixed index grating by simultaneous fixing is quite uniform inside the photorefractive crystal with comparison to by post fixing. The resulting diffraction efficiency of the fixed volume grating is mainly dependent on the initial intensity modulation of the two writing beams. The model also shows that fixing in a high doped material, at its developing stage, the electric grating can not be erased which resulting in low diffraction efficiency. A set of experimental demonstration are presented.