ABSTRACT
The term “high power CO2 lasers” is taken to mean those carbon dioxide lasers with average powers extending upwards from about 100 watts, currently up to around 10 kilowatts, which are mainly used for industrial processing. For lasers at the top of the power range, where the volume of gain medium is large, unstable resonators can offer considerable advantages. The cavity design can have important effects on practical aspects of operating the laser. As well as putting less demand on the stability of the mechanical structure, a reasonable tolerance to misalignment can ease the problem of restoring correct alignment after the optical components have been removed for inspection and cleaning. The possible effects of bouncing modes supported by reflections off the or “clutter”, also caused by reflections off the tube walls, should be is should be considered. This chapter discusses some of the main effects that have to be considered in the practical design of high power CO2 laser cavities.
