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Proceedings Paper

Generation Of Pseudo-Fizeau Fringes On Large Objects
Author(s): Victor Bennett
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Paper Abstract

For many years opticists have been contouring optical surfaces for deformations of the order of a few microns by the use of interferometric techniques. One of the earliest methods for doing this is to place a reference surface over the surface to be contoured. When this combination is illuminated by a coherent colli-mated beam, a fringe pattern is observed that is localized close to the surface that is being contoured. The fringe pattern (interferogram) is easily interpreted to yield contour information. This simple device (interferometer) is known as a Fizeau interferometer. (Ref. 1) As can be easily seen this experiment (and other interferometric techniques) is only applicable to surfaces which are smooth compared to the wavelength of the light used. The object must also have deformations from the reference surface not much larger than a few wavelengths of the light. In an effort to contour rougher surfaces and greater deformations than are allowed by using visible light, longer wavelength light such as the radiation from a CO2 laser is used. Unfortunately there exist many objects that are too rough and have too great a deformation to be suitable for an interferometer even with these longer wavelengths. At present, many of the objects of this type are handled by the conventional techniques of close-range photogrammetry (Ref. 2) and moire fringes. (Ref. 3)

Paper Details

Date Published: 1 October 1974
PDF: 8 pages
Proc. SPIE 0045, Coherent Optics in Mapping, (1 October 1974); doi: 10.1117/12.953973
Show Author Affiliations
Victor Bennett, The Institute of Optics (United States)

Published in SPIE Proceedings Vol. 0045:
Coherent Optics in Mapping
N. Balasubramanian; Robert D. Leighty, Editor(s)

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