涡旋光用于物体面内位移变形测量的模拟

Simulation of in-plane displacement deformation measurement using vortex beams

提出了一种利用涡旋光进行面内位移测量的新方法。将传统的电子散斑干涉测量技术与液晶空间光调制器(SLM)相结合,把利用SLM所获得的涡旋光应用于双光路电子散斑干涉,从而测量变形物体的面内位移。推导出了以平面光为物光、涡旋光为参考光以及涡旋光为参考光、物光时物体发生面内变形前后的干涉强度公式,模拟了变形前后的干涉图样,分析了干涉变形图样的特征。运用四步相移方法求出了物体的变形相位公式,通过解包裹得到了物体的变形相位。模拟结果与利用传统电子散斑干涉测量系统结合傅里叶变换法获得面内位移的变形相位分布是一致的,表明涡旋光可以应用于物体的变形测量,为物体面内位移变形测量提供了一种新途径。

In electronic speckle pattern interferometry experiment,object beam and reference beam are al ways plane light. We propose a new method for in-plan displacement measurement by application of vor- tex beams in double-optical path electronic speckle pattern interferometry. The method is based on the combination of traditional electronic speckle interferometry techniques and liquid crystal spatial light modulators. The vortex beams are generated by liquid crystal spatial light modulator, and the interference pattern of object beam and reference beam is captured by a CCD camera. We analyze two cases： vortex beam as reference light and plane beam as object light,where object light and reference light are both vortex beams. The interference intensity is calculated,and the interference fringe patterns are simulated before and after the object is deformed. The characteristics of fringe patterns are obtained. By four-step phase shifting method, the corresponding phase-maps are calculated. By unwrapping, we obtain the three- dimensional distribution of the in-plane displacement deformed phase. The simulation results are com- pared and validated with those obtained using Fourier transform method in electronic speckle pattern in- terferometry experiment system. The numerical simulation results support that this paper provides a new method for in plane displacement measurement.