Equilibrium temperatures in a CO2 TEA laser

Abstract

Equilibrium gas temperatures as high as 600±30 K have been observed in the center of a CO₂ TEA laser discharge by measuring the absorption of a CO₂ laser beam following the gain pulse. Uncertainties in the theoretical variation of absorption with temperature were avoided by measuring the absorption coefficient of the gas mix used in the laser in a temperature‐controlled oven, up to a temperature of 610 K, so that the observed absorption in the laser discharge could then be directly related to the gas temperature. The temperature decreased from the center of the discharge towards the sides, and was initially constant along the direction of the transverse current. A temperature increase was observed with input energy, while a decrease was observed with pressure, distance between electrodes, and flatness of the electrode profile. A temperature of approximately 450 K was optimum for maximizing the small‐signal gain in this system.