Research On Fizeau Phase-Shifting Laser Interferometer

Fizeau phase-shifting laser interferometer has been publicly recognized as an optical measurement instrument with high precision and high sensitivity, which is an indispensable tool for high-precision optical testing. Based on Zemax software, we set up a fizeau laser interferometer with diameter of 100 mm, which can be used to analyse the interference principle, as well as the influence from instrument testing-precision imposed by its internal composition in the present paper. It is very significant in practical engineering.Firstly, the article summarized the present development situation of the fizeau phase-shifting laser interferometer, and presented a design of 100 mm fizeau phase-shifting laser interferometer based on the principle of fizeau phase-shifting interferometry. In this work, it used sequence interface from Zemax as the platform to design plane and sphere interference system, and transformed these system data into the non-sequence interface of Zemax, and obtained the simulation plane and spherical interference fringe.Subsequently, With Matlab software as the processing platform, it adopted median filtering to preprocess the interference fringe. By analyzing the responses of various phase-shifting algorithms due to the instrument main error sources (phase-shifting error, second-order nonlinearity of detector, effects of multi-beam interference and high frequency noise), we chose to use the traditional four steps phase-shifting algorithm as phase extraction algorithm, and meantime the discrete cosine least-squares phase unwrapping algorithm also was employed to deal with wrapped phase, and got the diagram of wavefront phase.Finally, Zernike polynomials were employed to fit phase data and evaluate the quality of measured-wave, results show that the plane testing accuracy of this instrument is better than the PV 1/40 wavelength, and better than 1/24 wavelength for spherical testing accuracy.