Optimization research on optical structural parameters of point diffraction interference system

On the basis of analyzing the point diffraction wavefront error, the influence of the optical structural parameters, including the numerical aperture of objective lens, the size of pinhole and the numerical aperture under testing, on the point diffraction intensity also have been discussed in the paper. We have optimized the optical structural parameters gradually and obtained the parameters matching reference table. By comparing the measurement results by PDI system and Zygo interferometer, the difference of root mean square error is about /1000, and the interference pattern by PDI system have good contrast and brightness, which verify the rationality of the selected optical structural parameters.