斩波式自适应移相干涉技术

Chopping Adaptive Phase-Shifting Interferometry

研究对环境振动和空气扰动所造成的两相干光束间常数项光程变化不敏感的自适应移相干涉系统。利用偏振分光技术 ,采用闭环控制 ,并将高频振幅调制与锁相技术相结合 ,建立一斩波式自适应移相干涉系统 ,可对环境振动引起的干涉条纹的抖动进行实时探测并予以光程补偿 ,将干涉条纹依次锁定在与任意相位差相对应的位置。该方法不受两相干光束间光程差大小的限制且具有高信噪比。阐述了该方法的原理 ,描述了所建立的系统 。

An adaptive phase-shifting interferometry, insensitive to the disturbance of constant term of phase perturbations induced by environmental vibration and air turbulence is discussed. Where the polarization characteristic and high frequency intensity modulation of laser beam and phase lock-in as well as the closed loop control techniques are used, and a chopping adaptive phase-shifting interference system was set up. The wobble of interference fringes can be compensated, and sequentially be locked at arbitrarily chosen phase for phase-shifting testing. Compared with other similar techniques, here the depth of signal modulation is not limited by the magnitude of optical path difference and the fringe contrast is not reduced by the modulation, hence a high signal-to-noise can be obtained. The principle and structure of the chopping adaptive phase-shifting interferometer are described. The experimental results and conclusions are presented.