Investigation of influence of gas exit modes on characteristics of N2O - N2 - He discharge laser

A N2O laser is investigated in order to determine the influence of the composition, initial conditions, droplet parameters and supersonic 1-dimensional flow modes. The variations in the gain in a rectangular channel of an N2O - N2 - He GDL are calculated. The amplifying properties are measured experimentally as a function of the braking parameters, the nozzle parameters, the distance from the exit section of the nozzle and from the axis in the transverse direction and the composition of the mixture in 3-dimensional and flat jets. The amplifying characteristics of N2O - N2 - He mixtures are analyzed. It is found that amplification drops off sharply as the braking parameters increase, due to thermal dissociation of the working N2O molecules. Inversion exceeding 1015 cm-3 is achieved, which is higher in CO2 systems; the braking parameters are significantly smaller. Comparison of the experimental findings for N2O - N2, N2O - He and N2O - N2 - He mixtures indicate significantly more inversion for 1-dimensional flow behind a tapered nozzle than for a nozzle with maximum expansion.