Progress towards an optical clock

The development principles of a new optical clock are discussed. The basis for the optical clock is a transportable He-Ne/CH4 laser, which is created in our institute. The frequency division system consists of two lasers only: a CO4 laser and a submillimeter waveguide NH3 laser with optical pumping by a N2O laser. The frequency division system also includes a frequency synthesizer of MM range (similar to 100 GHz) with the use of an avalanche diode (similar to 100 GHz). In this report we present important results of the Schottky diodes investigation obtained at the Institute of Laser Physics, Siberian Division, Russian Academy of Sciences, and Semiconductor Institute (Tomsk) and also of the creation of the infrared laser for an optical clock. The results of absolute frequency measurements of the unperturbed (7-6)F-(2)P(7)(v3) methane line in 1993 and 1995 are reported. The experimental setup and the frequency measurement method are described. The following frequency values of the unperturbed (7-6) transition were obtained: in 1993, 88 376 181600041 (43) Hz and in 1995, 88376181600038 (35) Hz.