基于光纤导光的数字全息微形变测量系统

建立基于光纤导光的数字全息干涉微形变测量系统,首先,利用1×2单模光纤耦合器将激光源输出光分为照明光和参考光,实现光路结构简单、紧凑和稳定性好;然后,通过短焦距和长焦距准直透镜分别对照明光和参考光进行准直扩束,使得参物光强度接近1∶1,从而获得高信噪比的数字全息图。利用基于数字全息的双曝光方法对钢板的波长量级微形变进行实验测量。通过全息记录、再现及相位解包裹得到高精度的测量结果。实验结果表明,建立的基于光纤导光的数字全息微形变测量系统具有光路简单、稳定性好等特点,而且测量精度高。

Micro-deformation Measurement System by Digital Holography Based on Optical Fiber Laser Transmitting

A digital holographic micro-deformation measurement system is proposed based on optical fiber laser transmi-tting.Laser was coupled in 1×2 single mode optical fiber by convex lens,and two uniform laser beams were generated at end of the optical fiber.The two uniform laser beams were collimated and spread by convex lenses with different focus,and the intensity ratio of object beam and reference beam was close to 1∶1.The wrapped phase map resulted from wavelength-magnitude deformation of steel plate was produced with double-exposure digital holography.The unwrapped phase representing the deformation quantity of steel plate was obtained with Goldstein′s branch cut algorithm.According to experiment,the wrapped phase map based on this system has high s/n ratio.The system has simple optical path and high measurement precision with good stability.It gives references for practical application of digital holographic interferometry.