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Optical Engineering

Improvements In The Experimental Techniques Of Moire Interferometry
Author(s): Luciano Pirodda
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Paper Abstract

The paper presents some developments in the application techniques of double-exposure moire interferometry, with the aims of simplifying the technique and overcoming some of its current drawbacks. The main proposed development is the substitution of the classic interferometric setup, which records a high density grating on the specimen, by a high density, highly efficient double (crossed) holographic grating, clamped onto the object just in front of it. The following main advantages are recognized: Since the holographic grating is clamped onto the object and follows its rigid motion, the corresponding effect on the fringes Fs minimized. The coherence length requirements for the laser are minimized to a fraction of the distance from the grating to the object. An argon laser without etalon can be used, an obvious advantage given the low sensitivity of the photosensitive coatings. The specimen needs to be (doubly) exposed only once to obtain the two orthogonal sets of displacement fringes, thanks to the use of a crossed grating. Thus, errors due to the low repeatability of the test are avoided. Some applications, including the use of unusual photosensitive coatings and processing procedures, are presented.

Paper Details

Date Published: 1 March 1988
PDF: 6 pages
Opt. Eng. 27(3) 273219 doi: 10.1117/12.7977916
Published in: Optical Engineering Volume 27, Issue 3
Show Author Affiliations
Luciano Pirodda, University of Cagliari (Italy)

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