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Proceedings Paper

Flexure-beam micromirror spatial light modulator devices for acquisition, tracking, and pointing
Author(s): Troy A. Rhoadarmer; Steven C. Gustafson; Gordon R. Little; Tsen-Hwang Li
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Paper Abstract

The new flexure-beam micromirror (FBM) spatial light modulator devices developed by Texas Instruments Inc. have characteristics that enable superior acquisition, tracking, and pointing in communications and other applications. FBM devices can have tens of thousands of square micromirror elements, each as small as 20 microns on a side, each spaced relative to neighbors so that optical efficiency exceeds 90 percent, and each individually controlled with response times as small as 10 microseconds for piston-like motions that cover more than one-half optical wavelength. These devices may enable order-of-magnitude improvements in space-bandwidth product, efficiency, and speed relative to other spatial light modulator devices that could be used to generate arbitrary coherent light patterns in real time. However, the amplitude and phase of each mirror element cannot be specified separately because there is only one control voltage for each element. This issue can be addressed by adjusting the control voltages so that constructive and destructive interference in the coherent light reflected from many elements produces the desired far field coherent light pattern. Appropriate control voltages are best determined using a robust software optimization procedure such as simulated annealing. Simulated annealing yields excellent results, but it is not real time (it may require hours of execution time on workstation-class computers). An approach that permits real-time applications stores control voltages determined off-line by simulated annealing that produce key desired far field coherent light beam shapes. These stored results are then used as training data for radial basis function neural networks that interpolate in real time between the training cases.

Paper Details

Date Published: 5 July 1994
PDF: 13 pages
Proc. SPIE 2221, Acquisition, Tracking, and Pointing VIII, (5 July 1994); doi: 10.1117/12.178952
Show Author Affiliations
Troy A. Rhoadarmer, Univ. of Dayton (United States)
Steven C. Gustafson, Univ. of Dayton (United States)
Gordon R. Little, Univ. of Dayton (United States)
Tsen-Hwang Li, Texas Instruments, Inc. (United States)

Published in SPIE Proceedings Vol. 2221:
Acquisition, Tracking, and Pointing VIII
Michael K. Masten; Larry A. Stockum; Morris M. Birnbaum; George E. Sevaston, Editor(s)

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