Study On The Linnik Microscopic Interferometric System And Method Based On AOTF

With the development of the times,the demand of micro/nano structure devices is more and more,the required precision is also constantly improved,and the corresponding ultra-precision surface topography measurement technology is also increasingly required.It is a developing trend to change the measurement technology of surface topography from laboratory to industrial field.The interferometry technology based on wavelength modulation does not need mechanical scanning.It is suitable for industrial field,with fast measurement speed and strong anti-interference ability.In this paper,Linnik microscopic interferometric system is designed and built to realize multi-mode interferometry.The main research of this paper is wavelength scanning interferometry(WSI),variable wavelength phase-shifting interferometry,single wavelength phase-shifting interferometry(PSI).Therefore,the main work of this paper is as follows:1.Linnik microscopic interferometric system is designed and built.The system is compatible with wavelength scanning interferometry,variable wavelength phase-shifting interferometry,single wavelength phase-shifting interferometry,seamless switching and multi-mode interferometry.2.The wavelength scanning interferometry is studied.The selection of window function and the size of edge data points are determined by simulation analysis to improve the performance of the algorithm.Experiments on the linear scan wave number of AOTF show that the light source module works well.In order to verify the stability of the system,the absolute distance and step height experiments are carried out with WSI.Finally,the advantages of the wavelength scanning interferometry are determined by comparing the wavelength scanning interferometry with the white light vertical scanning interferometry.3.Research on the variable wavelength phase-shifting interference technology and the single wavelength phase-shifting interference Technology(PSI).Simulate the four-step phase-shifting method and the iterative method for the variable wavelength phase-shifting interference.Use the simulation to explain the advantages and disadvantages of the two methods and the reason for choosing the iterative algorithm in the final measurement.Use the actual experiment to verify that the iterative method is better than the four-step phase-shifting method in terms of accuracy.The single wavelength phase-shifting interference is used to measure the plane roughness,which proves that the mean filtering can improve the measurement accuracy of PSI,and the measurement step experiment shows that the system of PSI has good reproducibility.