Wavelength-Shift Interferometry: Using a Dither to Improve Accuracy
Jack A. Stone Jr., Alois Stejskal, Lowell P. Howard
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 of American Society for Precision Engineering
Stone Jr., J.
, Stejskal, A.
and Howard, L.
Wavelength-Shift Interferometry: Using a Dither to Improve Accuracy, Proceedings of American Society for Precision Engineering, Monterey, CA, USA
(Accessed December 2, 2023)