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|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|
|Keywords:||absolute interferometry,diode lasers,dither,interferometry,length measurement,wavelength-shift interferometry|
|Research Areas:||Manufacturing, Metrology|