POINT DIFFRACTION INTERFEROMETER

PROBLEM TO BE SOLVED: To provide a point diffraction interferometer enabling development of relatively high-intensity radiation, utilization of an interferometer analysis, and also use of an extended source emitting spatially-incoherent radiation. SOLUTION: The point diffraction interferometer is provided with an electromagnetic radiation source 1, a perforated mask 2 on its inlet end, an optical testing space 4 through which an optical system to be tested 9 can be inserted, means (5, 6) for generating a test beam and a reference beam by using a perforated mask 6 on its outlet end, and means (7, 8) for analyzing an interference pattern 16 generated by overlapping the test beam and the reference beam each other. A nearly-punctate through hole on an one- or two-dimensional array (12, 15) is incorporated into the perforated masks (2, 6) on both the inlet and outlet ends of the interferometer. One of its applications is, for example, a test optical system used for a photoengraving exposure system. COPYRIGHT: (C)2003,JPO