A novel adaptive phase-shifting interferometry

An adaptive phase-shifting interferometry, which is insensitive to the uniform optical path difference induced by environment vibration and air turbulence, is studied. An adaptive phase-shifting interference system based on high frequency amplitude modulation and phase lock-in technique is setup. This system can detect the wobble of interference fringes induced by environment vibration, compensate the optical path difference, and lock-in the fringe at any chosen phase difference. This method is not limited by optical path difference and can obtain a high SNR, and doesn't reduce the contrast of interference fringes. The principle and structure of the adaptive phase-shifting interferometer are described. The experimental results and conclusions are presented.