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Proceedings Paper

Profilometry by spectral encoding of the optical axis
Author(s): Herve Perrin; Patrick Sandoz; Gilbert M. Tribillon
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Paper Abstract

A scanning optical profilometer without sample displacement along the optical axis has been developed. Light coming from a wide spectrum light source is focused onto the inspected surface through a Fresnel lens. Because of its dispersive properties, the foci are distributed along the optical axis as a function of wavelength. The reflected light is focused on a filtering pinhole like in confocal microscopy. The only wavelength exactly focused on the surface is transferred through this pinhole to the detection unit. The detected light is analyzed through a spectroscopic device and the surface height is deduced from the wavelength for which the light intensity is maximum. This punctual measure is repeated for each surface point by a lateral scanning of the surface. With respect to other focus sensing profilers, we replace a mechanical z displacement of the sample by a spectral inspection of the detected light. The setup and some experimental results are presented.

Paper Details

Date Published: 12 December 1994
PDF: 9 pages
Proc. SPIE 2340, Interferometry '94: New Techniques and Analysis in Optical Measurements, (12 December 1994); doi: 10.1117/12.195933
Show Author Affiliations
Herve Perrin, Univ. de Franche-Comte (France)
Patrick Sandoz, Univ. de Franche-Comte (France)
Gilbert M. Tribillon, Univ. de Franche-Comte (France)

Published in SPIE Proceedings Vol. 2340:
Interferometry '94: New Techniques and Analysis in Optical Measurements
Malgorzata Kujawinska; Krzysztof Patorski, Editor(s)

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