Continuously operating high-pressure carbon dioxide lasers

A study was made of continuous-wave (cw) high-pressure CO₂ lasers with discharges in capillary tubes. The maximum pressure at which stimulated emission could be obtained was determined as a function of the radius and temperature of the discharge wall tubes, and of the rate of pumping of the gas mixture. A high-pressure CO₂ laser with a waveguide resonator was studied. The optimal relationship between the size of the field at the waveguide input and the guide radius was determined. A theoretical analysis was made of the possibility of achieving continuous emission at atmospheric pressure. A similarity principle was derived for a population inversion in a CO₂–N₂–He mixture at the maximum gas density in the case thermal excitation of the lower laser level. An analytic dependence of the gain on the gas density and tube radius was obtained. The results of these calculations were compared with the experimental data.