紫外光敏材料硅酸铋(BSO)在短波长的蓝紫光激励下电阻率会急剧降低, 可作为良好的光信息写入材料, 用作光寻址的液晶空间光调制器(LC-SLM)的感光层。介绍了以BSO为基的光寻址透射式液晶空间光调制器的结构和工作原理, 从BSO晶体产生光电导效应的机理出发, 得到了光电流和光照功率的关系, 实验测量了BSO晶体片在不同频率和不同强度的光照下的光电响应。通过对液晶分子指向矢分布随电压变化的理论计算, 得到了在不同光照强度下BSO基的液晶空间光调制器产生的光程差, 与实验中液晶盒在不同电压下产生的光程差有相同的变化趋势。

Bi12SiO20(BSO) is a kind of photosensitive material. Its resistance would drop sharply when exposed to the short-wave-length light, such as UV, so it would be used as the sensitizing layer in the liquid crystal spatial light modulator (LC-SLM). In this paper, we have theoretically studied the principle of LC-SLM and the photoconductivity of BSO. The relationship between photocurrent and the power of the illumination is introduced. In the experiment, the photoconductive effect of a slice of BSO with different wave-lengths illumination is measured. The optical path difference caused by the LC-SLM exposed to the UV is calculated by computing the distribution of the liquid crystal director. The change of the optical path difference caused by UV is similar to the change of optical path difference when the LC cell is applied different voltages in the experiment;