Fundamental and overtone band lasing in RF discharge supersonic CO laser

Radio frequency discharge CO overtone lasing with output power of 50 W was demonstrated with supersonic cooling system. The lasing was observed on 9→7, 10→4 and 11→9 vibrational transitions at around 2.7 μm wavelength. Fundamental band lasing was observed within 4.9 - 5.7 μm spectral range. Output power of 2.1 kW with efficiency of 21% was obtained in fundamental band. Modeling experiments on electron-beam sustained discharge overtone CO laser demonstrated that the time interval needed to populate high vibrational levels by W pumping is considerably more than transit time from the supersonic nozzle to laser resonator axis in the RF facility. Possibilities of supersonic overtone CO laser design improvement, for instance, gas pre-cooling and excitation in supersonic cavity were discussed.