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Proceedings Paper

Long-range phase-conjugate interferometry
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Paper Abstract

The most accurate method of measuring distance and motion is interferometry. This method of motion measurement correlates change in distance to change in phase of an optical signal. As one mirror in the interferometer moves, the resulting phase variation is visualized as motion of interferometric fringes. While traditional optical interferometry can easily be used to measure distance variation as small as 10 nm, it is not a viable method for measuring distance to, or motion of, an object located at a distance grater than half the coherence length of the illumination source. This typically limits interferometry to measurements of objects within <1 km of the interferometer. We present a new interferometer based on phase conjugation, which greatly increases the maximum distance between the illumination laser and the movable target. This method is as accurate as traditional interferometry, but is less sensitive to laser pointing error and operates over a longer path. Experiments demonstrated measurement accuracy of <15 nm with a laser-target separation of 50 times the laser coherence length.

Paper Details

Date Published: 1 September 2004
PDF: 12 pages
Proc. SPIE 5418, Spaceborne Sensors, (1 September 2004); doi: 10.1117/12.543824
Show Author Affiliations
Russell M. Kurtz, Physical Optics Corp. (United States)
Ranjit D. Pradhan, Physical Optics Corp. (United States)
Tin M. Aye, Physical Optics Corp. (United States)
Gajendra D. Savant, Physical Optics Corp. (United States)
Tomasz M. Jannson, Physical Optics Corp. (United States)
Marvin B. Klein, Lasson Technologies, Inc. (United States)

Published in SPIE Proceedings Vol. 5418:
Spaceborne Sensors
Robert D. Habbit; Peter Tchoryk, Editor(s)

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