A new version of interferometer construction for absolute distance measurement is presented. It is based on measuring the contrast of a two-wavelength interference pattern with using a CO2 laser generating a pair of optical wavelengths simultaneously.
Anatol N. Golubev,
Alexander M. Chekhovsky,
"Absolute distance interferometry with two-wavelength fringe visibility measurement," Optical Engineering 36(8), (1 August 1997). http://dx.doi.org/10.1117/1.601445