Efficiency of the vibrational excitation of CO2 molecules pumped by a capacitative discharge

An investigation was made of the distributions of the gain and input energy per unit volume along the discharge chamber length in a CO₂–N₂–He mixture stream excited by an rf discharge. The dependences of the gain and discharge luminescence intensity on the coordinate x were determined along the direction of the gas flow. The discharge luminescence intensity was shown to characterize the input energy distribution along the X axis. Calculations were made of the small-signal gain in the rf discharge. Experimental data on the distributions of the input energy and of the electric field in the discharge and the average values of the kinetic coefficients were used in the calculations. The efficiency of pumping CO₂ lasers with an rf discharge was found to be close to the dc pumping efficiency. The results obtained provide evidence of promising prospects for using an rf discharge in fast-flow industrial lasers.