Threshold pumping energy of a high-pressure pulsed electric-ionization CO2 laser

Theoretical estimates are obtained of the threshold energy of a high-pressure pulsed CO₂ laser on the assumption that the stimulated emission is due to a single rotational line of the P branch of the 0001–1000 band. These estimates are obtained as a function of the parameters of the resonator and of the CO₂ + N₂ + He working gas mixture. It is reported that the calculations are in satisfactory agreement with the results of experiments carried out on an electric-ionization CO₂ laser at pressures p up to 4 atm. The measured threshold values of the ratio E/p are also reported and it is shown that the presence of helium affects this ratio.