Polarization Phase-shifting Interference Microscopy For Ultra-precision Surface Topography Measurement

Surface topography is an important feature which affects the functinal properties of components.With the development of modern optics, photoelectron technology and aerospace technology, the needs for ultra-precision surface topography measurement and analysis is urgent. So, in this paper, the combination of polarization phase-shifting and Michelson microscopy, namely polarization phase-shifting interference microscopy, is proposed for ultra-precision surface topography measurement with innovation and practicability.Firstly, based on the actual engneering, the disadvantages of existing ultra-precision surface measurement methods are analysed, and then, the combination of polarization phase-shifting and Michelson microscopy, namely polarization phase-shifting interference microscopy, is proposed. Furthermore, theoretical analysis model of the proposed method is established. Secondly, polarization phase-shifting unit with high precision and compact structure, the mechanisms with stability and reliability to adjust the posture of reference mirror are designed.In addition, the system based on the proposed polarization phase-shifting interference microscopy is constructed.Thirdly, based on VC++ platform, the mearurement software matching the above system is built up, which consists of image capturing, data processing, 3-D topogragpy displaying and parameter evaluation.Finally, some comparison tests are conducted on the system. Consequently, the repeating measurement precision is proved to be better than 0.5nm, and the measurement error for Ra is less than 5%.The research and experiment results indicate that the developed system based on the proposed polarization phase-shifting interference microscopy has the characteristics of high precision, good stability and repeatability, and satisfies the needs for ultra-precision surface measurement.