CO2 laser wavelength standards

This paper discusses the possibilities of the CO2 laser for providing a very large number of accurate wavelength-frequency standards in the submillimeter to micrometer region of the spectrum and reviews measurements of the absolute wavelengths, including previously unpublished measurements, leading to a value of 9.305 385 635 μm for the R(14) transition, with an accuracy limited by the present definition of the international meter.