Spectrum analysis of low frequency vibration in interferometry

In order to reduce the influence of vibration on phase-shifting interferometry, the spectrum analysis of the vibration signal was carried out to separate the spectrum signal that contributed to the low-frequency vibration, which verified the fact that the phase-shifting interferometry (PSI) algorithm was more sensitive to vibration at 2 times the phase-shifting frequency. According to the standard PSI measurement steps and Newton's generalized binomial theorem, the multi-frequency vibration influence factor γ was derived. The phase error calculated by the standard PSI algorithm and the phase error after the multi-frequency vibration influence factor γ processing were simulated by Matlab software, and the experiment was carried out to verify it. The results show that the RMS value and phase error of the wavefront processed by the γ influence factor are lower than those of the PSI algorithm. The RMS value can be reduced by 22 times and the phase error can be reduced by 20 times.