Research On Interferometry Based On The Spatial Light Modulator

Digital shearography have proven to be excellent tools for displacement,deformation,and vibration measurements of object.Because of its high precision,non-contact and full field measurement,it has been widely used and studied in the field of engineering.However,once the system is built,the shearing amount is determined and fixed in the current system.It is impossible to adjust the shear flexibly according to the measurement condition,which is not conducive to the system integration and greatly limits the available scenarios of digital shearography.To overcome the limitations,a novel digital shearography using spatial light modulator is proposed.Based on the diffraction principle of binary optics,the shear can be adjusted flexibly while keeping the optical element unchanged.The influence of the shear on the digital shearography is deeply studied.The main work of this paper is as follows:(1)The optical path based on spatial light modulator is proposed and constructed,the beam split and the adjustment of shearing amount are realized using the proposed scheme.(2)A shearing interference measurement optical path based on the spatial light modulator is proposed to measure the thermal stress of the surrounding fixed disk.Share can be changed by the use of spatial light modulator as shearing device when the system is fixed.The phase-shifting device is simplified benefit from the use of time series method,thus the proposed scheme can realize real-time dynamic measurement.(3)The influence of shear on interference image and measurement result is studied.(4)The distribution of the theoretical value of the deformation of the measured object under heating is obtained by simulation.(5)The data processing program is compiled,and the interferogram is acquired and processed to obtain the displacement-derivative distribution.The displacement-derivative distributions is captured and analyzed when the share is different.