Nonlinear calibrating for phase-shifting adapter with three PZTs

A method to calibrate a phase-shifting adapter with three piezoelectric cer amics is proposed in this paper to increase the testing precision of phase- shifting interferometry. The fast Fourier transform method is used to calib rate each of the PZTs, and the spatial geometry algorithm is used to calcul ate the stretching differences of every PZT. According to the differences a nd the curves of displacement versus the step of the applied voltage to eac h PZT, in situ calibration of the phase-shifting adapter is allowed. Experi mental work shows that, after calibration by this method, the rotation of t he interferometer pattern and the change of fringe distances decline to 1 d egrees and 0.015 mu m. (C) 1999 John Wiley & Sons, Inc.