NIST logo

Publication Citation: Wavelength-Shift Interferometry: Using a Dither to Improve Accuracy

NIST Authors in Bold

Author(s): Jack A. Stone Jr; Alois Stejskal; Lowell P. Howard;
Title: Wavelength-Shift Interferometry: Using a Dither to Improve Accuracy
Published: January 01, 1996
Abstract: A dither in path length can dramatically improve the accuracy of wavelength-shift methods used for absolute distance interferometry. Here we report how a dither improves the accuracy of absolute distance measurement by two orders of magnitude, reducing errors from ~1?mm to ~10??m (1?s ). The dither is provided by modulating the position of a cube corner reflector in the reference arm of the interferometer. The modulation amplitude is on the order of 10??m, short relative to the synthetic wavelength associated with our wavelength-shift but much longer than the physical wavelength of our laser (670?nm). The effect of errors in our system that have periodicity of 1/2 wavelength can be largely eliminated by averaging results while modulating the path length.
Proceedings: Proceedings of American Society for Precision Engineering
Pages: pp. 357 - 362
Location: Monterey, CA
Keywords: absolute interferometry;diode lasers;dither;interferometry;length measurement;wavelength-shift interferometry
Research Areas: Metrology, Manufacturing