Interferometric measurement of grazing incidence for measuring a transparent plane-parallel plate

摘要

(57) [summary] interferometer [MEANS FOR SOLVING PROBLEMS] grazing incidence, includes a light source that has spread to limit the spatial coherence of the test beam and the reference beam. It is oriented the test plate to be a grazing incidence with respect to the test beam, As a result, the first part of the test beam is reflected from the front surface of the test plate, the second part of the test beam back side of the test plate is reflected from the surface of the two parts of the test the beams are separated from each other. Spatial coherence of the test beam is related to the lateral separation of the first amount test beam, of the second portion between the meaningful, the contrast of the interference fringe pattern between the surfaces of the front side and the back side of the test plate by this reduce. Also, is matched to only one of the two parts of the test beam, reference beam, and above the reference surface, the formation of the interference pattern between one of the faces of the front and back of the test plate and the reference surface give priority than the formation of the interference pattern between the other of the plane of the front and back of the test plate.