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Proceedings Paper

Long-wavelength laser diode interferometer for surface flatness measurement
Author(s): Peter J. de Groot
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Paper Abstract

Modern phase-shifting interferometers grew out of a traditional need for high-precision evaluation of polished optical components. The technology is very mature now, enough so that it is reasonable to look for other applications of these instruments. Some important industrial applications have been found, particularly in the data storage industry. However, there are still many applications where the speed and high accuracy of phase-shifting interferometry would be very desirable, but the surface-finish requirements to generate visible-wavelength interference fringes are impractical. One way to increase the range of surface finishes compatible with interferometric analysis is to increase the source wavelength. Improvements in the reliability and affordability of 1.55-micrometers wavelength distributed-feedback laser diodes has opened up a new wavelength region for interferometric metrology. The 2.5X increase in wavelength when compared to HeNe-based interferometers is sufficient to a variety of important parts ordinarily considered too rough or distorted for visible-wavelength interferometry.

Paper Details

Date Published: 15 November 1994
PDF: 5 pages
Proc. SPIE 2248, Optical Measurements and Sensors for the Process Industries, (15 November 1994); doi: 10.1117/12.194312
Show Author Affiliations
Peter J. de Groot, Zygo Corp. (United States)

Published in SPIE Proceedings Vol. 2248:
Optical Measurements and Sensors for the Process Industries
Christophe Gorecki; Richard W. T. Preater, Editor(s)

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