PHASE STEP CALIBRATION AND PHASE MEASUREMENT IN IMAGE PLANE HOLOGRAPHY USING BATIO3 CRYSTAL AS A RECORDING MEDIUM

A real-time visual approach for the calibration of phase step in image plane holography using BaTiO3 crystal as a recording medium is report ed. In this method, the diffuse object is illuminated symmetrically wi th two collimated beams and a pump beam is added at the crystal plane. Each illuminating beam generates an individual interferogram at the o bservation plane when the object is subjected to load. A rr phase shif t to one of the illuminating beams results in the complete disappearan ce of the fringes due to phase reversal between the individual interfe rograms, and at 2 pi phase change, the fringe pattern is restored. Aft er calibration, a single-beam illumination configuration is used for p hase measurement. We present the theory of the method and experimental results for a centrally loaded diaphragm rigidly clamped along the pe riphery. (C) 1998 Society of Photo-Optical instrumentation Engineers. [S0091-3286(98)01611-0].