光折变运动栅的性质

PROPERTY OF MOVING PHOTOREFR ACTIVE GRATING

在较一般的情况下，即包括扩散，漂移和光生伏打效应情况下，讨论了光折变运动光栅的性质。文中指出有两个干涉条纹的最佳速度可供选择，Ｖ_（ｏｐｔ）^（１）增强空间电荷场，因而提高了光折变相位栅的衍射效率，Ｖ_（ｏｐｔ）^（２）引起空间电荷场相对干涉条纹π／２空间相移，这是二波耦合产生光能流不可逆转移的必要条件．

The Property of the moving phase grating in the photorefractive materials is discussed for more general case, including diffusion, drift and the photovoltaic effect. There are two optimum velocity of the interference pattern that can be chosen. Vopt(1) enhances the spacecharge field, hence raises the diffraction efficiency of the photorefractive grating; Vopt(2) induces spatial phsse shift between the space-charge field and the interference pattern,this is the prerequisite for the optimized power exchange in tow-beam coupling.