Research On Vibration Measurement Method Of Orthogonal Polarize Laser Interferometer And Its Experiment

In the field of monitors of nanometer precise localization and displacement, the laser interferometer is non-contact and high precision measurement technology which is widely applied. It has been used in online measure, error compensating and control of exactitude machine tools, equipment applied in Large Scale Integration Circuit. It takes up an important position in the area of high precision measurement because of its reliability and practicability . Nonlinear error is an important factor which affects interferometer, and it is also important as an evaluation method in this paper.In this paper, a homodyne polarized laser interferometer had been researched. It could be used in high resolution, and high precision measurement of nanometer precise displacement.Parameter error and position error of optical components were important factors which affect nonlinear, so they were the key in this paper.Based on Jones matrices theory, the error source and action mechanism of polarized interferometer are analyzed by using four-channel orthogonal signals in nanometer level measurement. The main works and contributions achieved in this dissertation are concluded as follows:Firstly, an error model of the orthogonal polarize laser interferometer had been founded; and the effect and error of the polarization caused by each optical component were calculated and evaluated, in which wave plates affected interferometer the most. When its parameter error was 1°～5°, the system error was up to 8.8nm.We can select the the optical components and adjust optimal based on simulation results.Secondly, all the optical components and mechanical structures were selected based on theoretical analisis, the optical system was put up. And on-line evaluation had been used durting setting up the optical system, which simplified the process. The method of optimal adjusting was summarized on the base of the effect on the intensity and the lissajous figure.This method could decrease the nonlinear effectively.Lastly, the displacement measurement experiment had been done, and the nonlinear error after adjusting was 10nm, 80% lower than before, which applied good messuring signals to the signal processing system,and made the measuring precision of system reached nanometer magnitude.