利用激光全息干涉法测量微小机械变形方向

Measuring Direction of Mechanical Micro-Deformation by Laser Holographic Interferometry

提出用可分离双参考光两次曝光全息测量物体变形方向的方法。设计的光路系统用两个平面反射镜将一束扩展激光束分成两束参考光和一束物光,籍此记录物体变形下的可分离双参考光两次曝光全息图。该全息图再现的两个像的图层可以被分离,再现的全息干涉图上的条纹可通过改变曝光次序和微位移再现参考光虚点光源的位置而移动。物体变形方向、干涉条纹移动方向和反射镜位移方向以及曝光次序之间有确定的关系。该干涉图含有物体变形方向和位移数值两种信息。从理论上重点分析了物体变形方向信息所遵循的基本规律,并由此得出了测量物体变形方向的方法。最后给出了实验结果。实验表明提出的方法和理论是正确的,物体变形方向的检测正确率可达100%。

The method of measuring direction of mechanical deformation by detachable double-reference-beam double-exposure holography is proposed. In the optical system designed, a spread beam is divided into the two reference beams and one object beam by two planar mirrors. Thus the double-exposure interferogram of the measured object under constant deformation can be recorded. Two reconstructing images reconstructed by this kind of hologram may be separated. Interference fringes in holographic interferogram reconstructed may be moved by changing exposure sequence and displacing the positions of virtual point sources of reconstructed reference beams. There are determinate relations among the deforming direction of object, moving direction of interference fringes and displacing direction of the reflector as well as exposure sequence. Detachable double-reference-beam double-exposure holographic interferogram carries double informations on quantity and deforming direction of measured object. The deforming direction is analyzed emphatically in theory. Thereout the method of using detachable double-reference- beam double-exposure holographic interferometry to measure deformation direction is gained. Experimental results prove that the method and the analysis are right. Test validities of such method is 100%.