设计了基于光学涡旋相移技术的离面位移测量实验方案, 实现了电子散斑干涉中相移的数字控制.该方法利用输入液晶空间光调制器中的叉形光栅产生涡旋光束, 通过涡旋光束绕轴的旋转产生相移;同时, 产生的涡旋光束又作为参考光与物光干涉.实验中, 在物体发生离面位移前后依次输入四幅叉形光栅, 产生相移步长为π/2的涡旋光束, 利用CCD获得涡旋光与物光的干涉光场, 从而获得离面位移场的包裹相位;再通过解包裹, 获得物体离面变形的相位变化.光学涡旋相移法可应用于离面位移测量.

In order to realize the digital control of phase shifting in Electronic Speckle Pattern Interferometry (ESPI), a method for out-of-plane displacement measurement by applying phase shifting based on optical vortex was proposed. In the experiment, vortex beam is generated by a Reflective Liquid Crystal Spatial Light Modulator (LC–SLM), and the phase shifts are obtained by rotating the vortex beam around its axes. Vortex beam which is used as reference light interferes with object light, and the out optical field is captured by a CCD camera. Four speckle patterns with phase-step π/2 are captured by the CCD before and after the deformation, respectively. The phase difference of the deformed object is obtained by unwrapping. Experimental results demonstrate the efficacy of the proposed method for out-of-plane displacement measurement.