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Proceedings Paper

Scalable surface profiling using multiwavelength heterodyne interferometry
Author(s): Lenore McMackin
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Paper Abstract

Super-heterodyne array interferometry enhances the ability of a laser-based system to unambiguously measure surfaces with features that are much deeper than the optical wavelength. Super-heterodyning combines measurements of the surface made at different optical wavelengths to effectively create synthetic wavelengths that can be much larger than the optical regime. The additional information obtained from a set of measurements of the same surface taken at different wavelengths is used by a phase unwrapping algorithm to automatically reconstruct the surface phase profile without phase jumps. We describe the development of an automated heterodyne interferometry technique with scalable dynamic range for measuring the surface profile of surfaces with large deviations and step features. Combined concepts from phase shifting interferometry, super-heterodyne imaging, and multiple-wavelength holography are reviewed. A phase unwrapping algorithm is also described that is useful in the context of applications such as adaptive and deployable optics or automated inspection, that may require automatic effective wavelength selection for adaptive resolution in the measurement of surface deviation. Extension to fully automated surface measurement is discussed.

Paper Details

Date Published: 11 December 2003
PDF: 11 pages
Proc. SPIE 5162, Advanced Wavefront Control: Methods, Devices, and Applications, (11 December 2003); doi: 10.1117/12.511873
Show Author Affiliations
Lenore McMackin, Keyotee, Inc. (United States)

Published in SPIE Proceedings Vol. 5162:
Advanced Wavefront Control: Methods, Devices, and Applications
John D. Gonglewski; Mikhail A. Vorontsov; Mark T. Gruneisen, Editor(s)

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