Wavefront Reconstruction Method And Simulation Study Of Shearing Interferometry To Measure Optical Compenents

With the development of the national defense and tip science technology, high-precision optical systems are widely applied, which brings the growing demand on optical components and higher accuracy. It is the critical technology for obtaining high quality optical surface that is the availability of reliable and effective test. In traditional processing, the processing and detection is carried out separately, which leads low efficiency and low accuracy in processing. Therefore, it is the key to solve urgent need of optical components that is developing an incumbent detection technology and feedback processingin. Shearing interferometry is a kind of common path and compared with own interferometry without standard reference wavefront, which have the advatanges such as anti-jamming, anti-vibration, et al., and it is suitable for on-position measurement. However, the interferogram is not intuitive, and needs complex image processing and wavefront reconstruction, which limits its application. So it has important significance and value to study on the wavefront reconstruction method of shearing interferometry.Firstly, interferogram image needs processing. Generally speaking, the interferogram image obtained from interferogram is distribution by intensity, and not by phase distribution. The processing for interferogram image includes two steps. The first step is obtaining phase distribution of the interferogram image from intensity distribution, which uses the four-step phase shift method or spatial carrier method based on Fourier transform; and the second step is unwrapping phase using unwrapping methods. The issue writes the program of the two steps, which provides the interferogram image processing program.Secondly, wavefront reconstruction is needed. Basis on studying the wavefront reconstruction algorithm, write the wavefront reconstruction program using least squares fitting algorithm based on Zernike polynomials and reconstruction algorithm. Then the flow chart of the key module and process are provided, which provide wavefront reconstruction program for the shearing interferometry system to measure the optical components.Finally, according to the lateral shearing interference principle and the wave aberration formula, the issue obtained shear interferogram in various wave aberration. Then analysis the influence on the accuracy which is brought by some factorssuch as the shear rate, order of fitting, wave surface function and solution of equation method, and improve the accuracy in wavefront reconstruction.Took parabolic mirror as an example, carried out simulation of lateral shear interferometry, simulation results show that image processing program and wave front reconstruction algorithm program correctly, they can be used for data processing of shearing interferometer.