研究一种基于干涉法测量液晶空间光调制器(LCSLM)的相位调制特性。利用合适的光路将一束激光分成两束并分别经过LCSLM,通过改变LCSLM中局部图像的灰度值,使其中一束光的相位发生变化,另一束保持不变。经过LCSLM后,两束光形成干涉条纹并被CCD接收,再根据干涉理论分析出SLM的相位调制特性。实验结果表明该SLM调制的相位与灰度值非线性关系,该方法能有效测出任意透射式LCSLM的相位调制特性。 A phase modulation based on interference method for liquid crystal spatial light modulator (LCSLM) is studied. Using a suitable optical path, a laser beam is split into two beams and passes through LCSLM respectively. By changing the gray value of the local image in LCSLM, the phase of one of the beams changes and the other remains unchanged. After LCSLM, the two beams form interference fringes and are received by the CCD, and then the phase modulation characteristics of the SLM are analyzed according to the interference theory. Experimental results show that the SLM modulation has a nonlinear relationship with the gray value. This method can effectively measure the phase modulation of any transmissive LCSLM.