Electric-discharge convection lasers

Research on several different types of high-power N2-CO2electric-discharge convection lasers (EDCL) has been in progress at the United Aircraft Research Laboratories since early 1967. The performance characteristics of one of these lasers, the coaxial EDCL, is described. The distinctive feature of the EDCL is the removal of heat (and, hence, prevention of thermal population of the 100 level of the CO2) from the laser cavity by gas convection rather than by wall cooling as in conventional N2-CO2lasers. The geometry of the coaxial EDCL is similar to the conventional N2-CO2lasers, with the flow, electric discharge, and optical cavity essentially aligned along the axis of a cylindrical laser tube. However, the EDCL is substantially shorter in length than conventional lasers with comparable power output. Results of experiments utilizing a high-Q optical resonator to determine the effects of flow conditions and discharge parameters on laser performance at the multikilowatt level are described. Also the performance characteristics of the EDCL in open- and closed-cycle operation are compared.