Mechanism of pulse emission from high-pressure electricdischarge He–Ar, Kr, Xe infrared lasers

A study was made of the time dependences of the amplitudes of stimulated and spontaneous emission from pulsed electric discharges in He–Ar, Kr, Xe mixtures, and the processes involved in populating the active levels were analyzed. Direct and stepwise excitation by electrons was taken into account, as was population resulting from relaxation processes (collisions of the second kind with electrons, radiative cascades, recombination processes, collisions with atoms of the active and buffer gases, excitation transfer from the helium molecules). A qualitative picture was obtained of the characteristic processes for populating the atomic levels of Ar, Kr, and Xe as a function of the composition and pressure of the mixtures. It was established that the decisive mechanism at high pressures involves direct excitation by electron impact from the ground states.