电控液晶光栅在卫星激光通信、激光雷达的光束指向应用中具有体积小、光束灵活可控的优势。而获取电控液晶光栅对光波前的相位调制分布则是评价液晶光栅性能的关键。提出液晶光栅调制波前相位的共轭移相干涉测量技术，通过实验对比验证了实测远场分布与近场相位计算远场分布的一致性，由此可实现由近场相位测量的光束指向控制新方法。

Electronically controlled liquid-crystal gratings have advantages such as small volume and agile optical beam steering in satellite laser communication and laser radar. However, the key issue for performance evaluation of liquid-crystal gratings is to obtain the modulated beam wavefront by it. Conjugation phase shifting interferometry measuring liquid-crystal gratings wavefront is presented. In the experiment, the measured far-field intensity is in accordance with the theoretic analysis on near-field wavefront. This technology shows a new beam steering control method with near-field wavefront measurement.