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Optical Engineering

Interferometric testing of plane and cylindrical workpieces with computer-generated holograms
Author(s): Sven Brinkmann; Roland Schreiner; Thomas Dresel; Johannes Schwider
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Paper Abstract

Increasing demands for accuracy and speed in manufacturing and international standards of quality control require faster and more precise measurement techniques. Surface inspection and shape control of technical workpieces is commonly done by tactile profilometers. A faster alternative to this mechanical tool can be realized interferometrically. Grazing incidence of laser light onto the technical surface reduces speckle noise significantly. In our setup computer-generated holograms (CGHs) are used both as references for the technical surfaces to be tested and as beamsplitter or recombining element. Each class of workpieces requires specific CGHs, e.g., phase gratings for plane surfaces or diffractive axicons for cylindrical and conical surfaces. An ideally shaped workpiece will result in a zero fringe field. Deviations from the ideal shape will be indicated by interference fringes and fringe distortions. The sensitivity of the interferometer can be adapted to technical needs. The surface deviations of the workpiece are superimposed by adjustment aberrations which can be described mathematically with sufficient accuracy and eliminated by a least squares fit. This measurement technique is demonstrated with workpieces of different shape.

Paper Details

Date Published: 1 September 1998
PDF: 6 pages
Opt. Eng. 37(9) doi: 10.1117/1.601759
Published in: Optical Engineering Volume 37, Issue 9
Show Author Affiliations
Sven Brinkmann, Univ. Erlangen (Germany)
Roland Schreiner, Univ. Erlangen-Nuernberg (Germany)
Thomas Dresel, Univ. Erlangen-Nuernberg (Germany)
Johannes Schwider, Univ. Erlangen-Nurnberg (Germany)

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