1 January 1987 Two-Wavelength Laser Interferometry Using Super-Heterodyne Detection
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Proceedings Volume 0813, Optics and the Information Age; (1987) https://doi.org/10.1117/12.967129
Event: 14th Congress of the International Commission for Optics, 1987, Quebec, Canada
Two-wavelength interferometry is well known since years and often used for ranging and contouring at reduced sensitivity 1. Recently, two-wavelength heterodyne interferometry has been reported, which can be applied for both, smooth and rough surfaces 2. However, this method is limited to large wavelength differences, which can be optically separated (prism, grating). By the availability of tunable diode-lasers as light sources, multiple wavelength interferometry with small wavelength differences is getting increased practical interest 3. It is the purpose of this paper to present a novel method, based on super-heterod e detection, which allows to make high resolution measurements at 241-- I effective difference wavelengths Λ = λ1 λ2λ1- shorter than 30 cm, without being obliged to have interferometric stability at the optical wavelengths Xi and1. itse and to separate these wavelengths optically. This is of great importance for range finding and industrial distance measuring with submillimeter resolution.
© (1987) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
R. Dandliker, R. Dandliker, R. Thalmann, R. Thalmann, D. Prongue, D. Prongue, } "Two-Wavelength Laser Interferometry Using Super-Heterodyne Detection", Proc. SPIE 0813, Optics and the Information Age, (1 January 1987); doi: 10.1117/12.967129; https://doi.org/10.1117/12.967129

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