Current, voltage and pressure perturbations induced by laser oscillation in the CO-He-Xe laser

Experimental measurements are reported for the perturbations in discharge current, voltage and gas pressure when laser radiation is chopped on and off in a sealed room-temperature CO-He-Xe (1.3:18.7:2.0) laser. When laser oscillation occurs there is less gas heating due to fewer CO-He V-T collisions and fewer CO-CO V-V-T collisions, with both processes involving CO in high vibrational levels of the ground electronic state. The reduced heating during laser oscillation leads to an increased gas number density in the discharge with a consequent increase in discharge impedance. Pressure perturbations are due to the increase in tube voltage which causes gas heating, together with additional effects arising from increased CO-CO₂ V-T collisions.