Phase Shift Interferometer Vibration Technology Research

Phase-shifting interferometer has wide applications in many fields including the testing of optical components and optical systems.But the accuracy of phase-shifting interferometry is generally limited by the environment vibration and air turbulence,especially for large optical components testing.It's necessary to improve the ability of vibration-insensitive for interferometric testing.In this paper,two methods are used to build theoretical modals of the phase errors caused by vibration,one is the frequency spectrum analysis method.The other is the Bessel function method.The simulation results show that the phase errors become smaller with the increase of the vibration frequency.The measurement is mainly influenced by the vibration with low frequency and large amplitude.The phase error will have a maximum or minimum when the vibration frequency equals the integral phase shifting frequency.The phase measurement error shows on the phase map as a ripple with twice the spatial frequency of the original fringe pattern and can't be reduced by means of averaging the several testing results.Based on the analysis of the phase measurement error caused by vibration,a new vibration insensitive algorithm called DLSIA(Double Least-Squares-Based Iterative Algorithm)algorithm is presented in the paper.AΦ130mm standard part is tested in the vibration environment,the comparative results show that the measurement accuracy of the DLSIA is higher than the 13 bucket algorithm by 0.0746λ(PV).In this paper,the phase error theory is built and explains specifically the reasons why environmental vibrations can cause phase errors.It is also instructive to the choice of the phase-shift algorithms in the corresponding vibration environment.Both results of the numerical simulations and the experiments show that the DLSIA algorithm has higher measurement precision,it will be a good and low cost solution for the measurement of the large optical components in the vibration environment.