Abstract

The question of contamination in laser gas mixtures is important, particularly when laser output power is severely limited. In these cases, it is useful to know how the level of contamination is related to degradation of laser performance. When the laser body is sealed, analysis via an intrusive technique obviously cannot be done without drastically altering the environmental conditions in which the laser is operating. In this study, impurity levels of contaminants are quantitatively evaluated while maintaining the operating conditions of the laser discharge. This evaluation uses the technique of optical emission spectroscopy to monitor emission in sealed helium-neon laser systems. The effect of impurities such as N₂, O₂, CO, and hydrocarbons on optical emission is discussed. The emission spectra for these species depend largely on their concentrations. This technique starts with mixtures containing known concentrations of contaminants prepared in very clean conditions. The sample is then discharged under the same pressure and discharge current at which the laser is normally run. The optical spectrum is taken over the desired wavelength region and analyzed with a high resolution (3/4 m) monochromator.

© 1986 Optical Society of America