We propose a two-wavelength interferometer that is used to a stroboscopic step height measurement. Different from most two-wavelength interferometers, in present experiment, two slightly different wavelengths are simultaneously oscillated by currently and thermally controlling a laser diode to work at mode hop region. By use of this two-wavelength laser source, a Twyman-Green interferometer, whose reference arm and object arm have known step height r and unknown step height h, respectively, is constructed. Three independent interference patterns corresponding to different OPDs are formed and they can be simultaneously taken by a CCD camera. Furthermore, tilting the reference, spatial frequencies are introduced into the interference patterns. Taking the Fourier transform of these patterns, three fringe amplitudes are obtained and their expressions can be solved for the unknown step height. As we can capture clear image of the interference patterns in a very short time by use of the high speed shutter function of the CCD camera, the error induced by the external disturbance is farthest reduced.
内容記述
Two- and three-dimensional vision systems for inspection, control, and metrology : 29-30 October 2003 : Providence, Rhode Island, USA. : Oct 2003, Providence, RI
雑誌名
Proceedings of SPIE - the International Society for Optical Engineering
巻
5265
ページ
127 - 133
発行年
2004-02
出版者
International Society for Optical Engineering, SPIE
ISSN
0277786X
書誌レコードID
AA10619755
DOI
info:doi/10.1117/12.518642
権利
Copyright 2004 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.
Stroboscopic step height measurement with two-wavelength interferometer using single diode laser source
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