Effects ofO2on low-pressure CO-laser discharges

Abstract

Trace additions of several gases are known to significantly effect CO-laser power and efficiency. Since small concentrations of additives are generally involved, these additives are recognized as predominantly influencing the characteristics of the laser plasma. Oxygen has been an additive receiving substantial attention in past measurements. In this paper we develop a consistent interpretation for all the observed oxygen effects both from our laboratories and elsewhere. Oxygen in small concentrations will be shown to improve laser efficiency and power through its effect on the electron-ion recombination process. At higher oxygen additions, laser output is degraded as a result of vibrational-translation relaxation by oxygen atoms. In addition, carbon formation and removal, plasma heating and cooling effects, heterogeneous loss processes, and the influence of polymer ions will be discussed through model calculations.