Phase-shifting interferometry immune to vibration

A modification of phase-shifting interferometry is proposed for microsurface profiling of flat surfaces under vibrating conditions. With this technique the required phase shift, achieved by quarter-wave plates and polarizers. is free of errors associated with motion. A nearly common optical-path configuration is achieved, and the effect of environment is reduced. The effect of environment on the optical system is also studied. Moreover, the measurement of phase is instantaneous, which increases the versatility of this technique to measure vibrating objects. Experiments were carried out on a smooth mirror surface excited with high-frequency vibrations, and the technique was found to be immune to vibrations of both high and low frequency. (C) 2001 Optical Society of America.