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.