由于激光器发出的光束通常在毫米量级，然而在激光测距、激光通信、激光全息等领域中需要较宽的光束，因此需要对激光束进行准直扩束。本文提供了一种基于LC-SLM的变倍率激光扩束方法，利用LC-SLM产生透镜的波阵面。由计算机数值模拟出焦距不同的变焦透镜相位调制图，将其加载到LC-SLM上，利用焦距不同的变焦透镜相位调制图的灰度信号来控制LC-SLM外加电压变化，实现了基于LC-SLM的变焦透镜功能。根据伽利略望远镜形式的扩束系统，本文利用LC-SLM的变焦透镜功能与匹配透镜配合，搭建了基于LC-SLM的变倍率激光扩束系统，实现对激光束的变倍扩束。实验结果表明，该系统实现了2×~10×连续变倍率激光扩束。系统结构简单、精度高、响应速度快，具有很大的实用价值。

It needs a wider beam in laser ranging, laser communication, laser holography and so on，but the laser beam is in the millimeter scale, therefore, collimating and expanding the beam of the laser beam is needed. This article provides a variable-rate laser beam expanding method based on LC-SLM. Using LC-SLM to produce the wavefront of a lens，The phase modulation graph of the zoom lens with different focal length is simulated by the computer. It is loaded on the LC-SLM, and the change of the LC-SLM applied voltage is controlled by the gray signal of the phase modulation graph of the zoom lens with different focal length. The function of the zoom lens based on the LC-SLM is realized. According to the beam expansion system of Galileo telescope, in this paper, a variable rate laser beam expansion system based on LC-SLM is built by using the function of the zoom lens of LC-SLM and the matched lens to achieve the multiplex beam expansion of the laser beam. Experimental results show that the system realizes continuous variable rate laser beam expanding at 2×~10×. The system has simple structure, high accuracy and fast response speed, and has great practical value. It is of great practical value.