PERFORMANCE OF A SPATIAL-FILTERING DETECTOR APPLIED TO A SPECKLE DISPLACEMENT SENSOR

The performance of a spatial filtering detector with a comb-shaped photosensitive area, applied to a speckle displacement sensor, is studied by using correlation analysis of its output signal. The coherence of the output signal, which plays the most important role in the measurement, is examined in conjunction with the displacement and the decorrelation of speckle patterns on the detector, which depend on the optical configuration of the measured system. The desirable condition for matching between the structure of the detector and beam diameter on the object has been considered. The theoretical relations have been verified by experiments.