Heterodyne Interferometric Analysis System

Abstract

A heterodyne interferometer system is described which incorporates a two-dimensional CCD photodetector array to provide accurate optical phase measurements of a wavefront at each of its 244 by 190 detector locations. The intensity of each detector is digitized and read directly into the memory of a Data General Eclipse computer at a rate of approximately 2.5 x 106 pixels per second. The phase is calculated using the 3-bucket technique described below. The basic interferometer is a Twyman-Green (LUPI). A 320 x 240 element 16 grey level or color graphics display helps in quickly accessing figure quality from the map of calculated phase values.