Stimulated emission from the recombining afterglow of an electron-beam discharge in several atmospheres of helium

Abstract

Stimulated emission from excited states of He2 has been observed as a consequence of the collisionally stabilized recombination of He2+ ions with electrons in the afterglow of a pulsed gigawatt electron-beam discharge into 3 atm of helium. Peak gains of the order of 0.04 cm−1 were found in components of the 3s3Σu+→ 2p3Πg transition of He2 in the 6400-Å region by directly measuring the time-resolved gain spectra using a tunable dye laser.