Measurement of singlet oxygen concentrations in a fast flow dc discharge in oxygen–argon mixtures

Abstract

Production of singlet delta oxygen (SO) by a dc glow discharge in flowing O2 : Ar mixtures has been investigated. SO concentrations have been measured with dilution of oxygen up to O2 : Ar = 5 : 95 at a pressure up to 14 Torr and specific power load in the discharge up to 50 J mmol−1. The largest relative SO concentrations achieved in experiments exceeded 9%. This is sufficient to obtain population inversion and laser gain in the oxygen–iodine medium.It was found that for the mixtures with large Ar content stray spectral lines appear near the SO 1268 nm band that is used to determine the SO concentration. These are the Ar I lines and their intensities increase relative to the SO band with Ar content. To estimate their contribution it is suggested to normalize their intensities on the intensity of the 1280 nm line.