Abstract
A technique to align automatically the beams of displacement-measuring interferometric gauges is described. The pointing of the launched beam is modulated in a circular pattern, and the resulting displacement signal is demodulated synchronously to determine the alignment error. This error signal is used in a control system that maintains the alignment for maximum path between a pair of fiducial hollow-cube corner retroreflectors, which minimizes sensitivity to alignment drift. The technique is tested on a developmental gauge of the type intended for the Space Interferometry Mission. The displacement signal for the gauge is generated in digital form; and the lock-in amplifier functions of modulation, demodulation, and filtering are all implemented digitally.
© 2002 Optical Society of America
Full Article | PDF ArticleMore Like This
Min-Seok Kim and Seung-Woo Kim
Appl. Opt. 41(28) 5938-5942 (2002)
Euan Morrison, Brian J. Meers, David I. Robertson, and Henry Ward
Appl. Opt. 33(22) 5041-5049 (1994)
Sheng-Hua Lu, Ching-I Chiueh, and Cheng-Chung Lee
Appl. Opt. 41(28) 5866-5871 (2002)