Measurements of the population of the upper laser level of the CO2 molecule and of the active-medium gain in a waveguide discharge channel

An investigation was made of the dependence of the population of the upper laser level of the CO₂ molecule on the pressure of the CO₂+N₂+He active mixture by recording the gas-discharge luminescence intensity at the 4.3μ wavelength. It was found that the population of the upper laser level is proportional to the discharge current at low pump intensities and is weakly dependent on the active mixture pressure p in the range 70–120 Torr. The results are given of experimental measurements of the small-signal gain at 10.6μ as a function of the discharge parameters. A comparison is made between the experimental data and analytic calculations.