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Optical Engineering

Simultaneous and real-time measurement of slope and curvature fringes in thin structures using shearing interferometery
Author(s): Hareesh V. Tippur
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Paper Abstract

A real-time lateral shearing interferometry that uses a pair of Ronchi gratings to perform wavefront shearing operations is described for measuring slope and curvature fringes simultaneously in thin structures. It involves simultaneous imaging of diffracted wavefronts using Fourier filtering. Two sets of fringe patterns, one representing slopes and the other curvatures, occur simultaneously at spatially distinct locations on the image plane, thereby eliminating the need for additional postprocessing of the recordings. In this work, the principles involved in the measurement of slopes and curvatures using this technique are explained. The method is then demonstrated on thin structures subjected to well-defined loading conditions, such as a clamped circular silicon wafer subjected to central displacement. Measurements have been successfully compared with analytical solutions.

Paper Details

Date Published: 1 December 2004
PDF: 7 pages
Opt. Eng. 43(12) doi: 10.1117/1.1809611
Published in: Optical Engineering Volume 43, Issue 12
Show Author Affiliations
Hareesh V. Tippur, Auburn Univ. (United States)

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