Decay Rates of Metastable Helium Atoms and Laser Enhancements in Afterglow Period

Abstract

The decay rates of the singlet and the triplet metastable atoms of helium and those of the helium-neon mixture are measured by an absorption method. The absorption tube is excited by the pulsed r.f. which is the same as the pulse operation of the laser. The afterglow of the neon line corresponding to the 2p4–1s4 transition is measured simultaneously. From the decay of the triplet metastable helium atoms and the decay of neon line in the afterglow, the enhancement of the 1.153µ laser oscillation in the afterglow period is investigated. Because the decay of the singlet metastable helium atoms is faster than that of the triplet metastable helium atoms, the visible laser oscillation at 6328Å is not enhanced in the afterglow period.