Radiation-induced perturbations in CO and Xe sidelight in the CO-He-Xe laser

Laser oscillation in a sealed-off room-temperature CO-He-Xe laser was observed to perturb CO and Xe sidelight intensities in the laser discharge. Bands of the CO fourth-positive group (A ¹ Pi to X ¹ Sigma ⁺) with v'=1-5 and 7 were enhanced during laser oscillation, while those with v'=6 and 8 exhibited no change in intensity. Bandheads of the CO third-positive group (b ³ Sigma ⁺, v'=0, 1 to a ³ Pi _r) were either enhanced or inhibited during laser oscillation depending on the discharge conditions; tail intensities of the third-positive bands, however, were always inhibited. Near-infrared Xe lines were enhanced (by up to 190%) during lasing. The excitation routes for the CO bands and the Xe lines have been identified, and the effects of laser oscillation on those routes are explained in terms of altered rates during lasing of electron-impact processes and collision-induced energy transfers.