A gas laser needs resonator gases, in order to be able to generate laser light. In a carbon dioxide laser, the gas mixture contains 60-85% helium, 13-55% nitrogen and 1-9% carbon dioxide. The exact composition varies, depending on the laser type and manufacturer. Certain types of lasers also require small additions of other gases e.g. oxygen, hydrogen, xenon and carbon monoxide. Toxic gas components require extra safety measures with respect to the gas supply system.
Gas mixtures for excimer lasers often consist of 0.05-0.3% halogens (fluorine or hydrogen chloride), 1-10% noble gases (krypton, xenon or argon) and 90-% buffer gases (helium or neon). For safety reasons, halogens must always be diluted with helium or neon.
A modern CO2 laser requires high purity resonator gases. The occurrence of impurities reduces the laser’s capacity, for example by lowering output and disturbing the electric discharge while increasing the wear on the laser’s optics. In this context, the most damaging impurities are water vapour and hydrocarbons.
As a rule, impurities in the resonator gases do not originate in gas cylinders; in most cases these are introduced via incorrectly designed gas supply systems. A reliable and satisfactory laser therefore requires that the choice of components and installation be left to specialists.
Laser gases for carbon dioxide lasers are supplied in separate gas cylinders and are mixed in the laser via a mixer, or as pre-mixed gases. All gases are included in the LASERLINE program. The LASERMIX program includes premixed resonator gases for most lasers.
