FRINGE PATTERN DISCRIMINATOR FOR GRAZING INCIDENCE INTERFEROMETER

摘要

Flatness and thickness variation information concerning transmissive plane-parallel test plates is obtained from a grazing incidence interferometer modified to distinguish between superimposed interference patterns containing both types of information. The grazing angle of the interferometer is varied, and unique modulation frequencies of local fringe intensities within the superimposed interference patterns are identified. The local fringe intensities attributable to the different interference patterns are distinguished by their respective modulation frequencies.