The Research Of Wavelength-tuned Phase-shifting Interferometry

While inspecting the profile of optical surface, people often face the problem of profile testing of transparent plates, and it can't been solved in ordinary method of interference.In this paper, we introduce the wavelength-tuned phase-shifting interferometry to measure the profile of transparent plate, and research the method deeply. We have finished the design of measure system according to the principle and set up the measuring system according to the design. The system includes two main parts:(l)hardware: interference system, lamp-house of interference system, image gathering system, and photography system.(2)software: phase-shifting algorithm, phase-unwrapping, phase image fitting with Zernike polynomial, and the output of measuring results.Some experiments have been done. It is shown that the wavelength-tuned phase-shifting interferometry can not only test common optical surface but also measure the profile of transparent plates. The system's measuring accuracy of common optical surface PV is better than X /40, its measuring accuracy of profile PV for transparent plate is better than X /25, and the accuracy of its RMS is better than X /100. In addition, two means of phase-unwrapping and two phase-shifting algorithms have been analyzed, and their measuring results have also been compared with each other.