Optical Characteristics of a 3kW DC Discharge-Excited CO Laser

Optical characteristics of a transverse DC discharge-excited 3-kW CO laser were investigated experimentally. Significant changes of oscillation spectra with gas temperature and a resonator position were observed. The number of oscillation lines for single-line oscillation was about three times as many as normal multi-line oscillation. A novel averaged small signal gain coeffi-cient for the multi-line oscillation, which could be used for the Rigrod's formula, was defined. This is useful to design an optimum resonator also for multi-line oscillation. The small signal gain coefficient increased with decreasing gas temperature and gas pressure. The spatial dis-tribution of the small signal gain coefficient was measured, showing a strong asymmetry effect of DC discharge. The maximum of the averaged small signal gain coefficient was 0.40m-1 and that of a localized small signal gain coefficient was 0.7m-1.