ACCURACY OF THE COMPUTER-CONTROLLED LASER FREQUENCY STANDARDS BASED ON RESOLVED HYPERFINE-STRUCTURE OF A METHANE LINE

Results of 2-year frequency comparisons of our transportable He-Ne laser standard stabilized on a component of the magnetic hyperfine structure (MHFS) of the F-2(2) line of methane lambda = 3.39 mu m, with our stationary laser using resolved recoil doublet as reference are presented. The absolute frequency of the transportable laser measured at PTB (Physikakisch-Technische Bundesanstalt, Braunschweig, Germany), using the radio-optical frequency chain, was transferred to the stationary device. On the basis of the theoretical model of the line shape, the frequency of unperturbed transition has been calculated.