Population processes in high-pressure inert-gas-mixture lasers

The amplitude-time structure of the laser and spontaneous emission following a pulsed electric discharge in mixtures of He + R (where R is Ar, Kr, and Xe) and Ar + Xe are investigated to analyze the working-level-population processes. The analysis takes into account the direct and stepwise excitation by electrons, and of population as a result of relaxation processes including type-two collisions with electrons, collisions with the atoms of the working and buffer gases, and excitation transfer from helium molecules. It is suggested that inversion is produced in the lasers as a result of direct electron collision with the ground state working atoms, and that increasing the working-gas pressure leads to a decrease of the parameter E/N and to a relative decrease of the number of fast electrons in the discharge.