Recombination lasers in a flowing negative glow discharge

Abstract

A fast gas flow through a negative glow plasma creates an afterglow region where supercooled electrons are separated from energetic beam electrons to produce a population inversion by collisional recombination. We report spatially-resolved electron temperature measurements of the afterglow plasma showing electron temperatures in the range of 750-1100 K under steady-state conditions. A 4 cm long flowing hollow cathode discharge was used to obtain CW recombination laser oscillation in ArI. Collisional recombination of singly- and doubly-ionized metal vapor species in the same type of plasma has also produced pulsed laser action in infrared lines of PbI, ZnI, PbII, and SnII. The addition of H2 is demonstrated to significantly increase the laser output intensity.