A feasible concept for a 100-kW cw CO 2 laser based on an existing 6-kW system

Abstract

The carbon dioxide laser uses as the light amplifying medium a weakly ionized mixture of carbon dioxide, nitrogen and helium (glow discharge). Pumping is performed automatically by interparticle collisions and light output per unit volume is considerably high up to several watt per cubic centimeter. Thus carbon dioxide lasers were most successful in generating high powers, where several construction schemes have been developed during the last twenty years as for instance slim cylindrical plasmas (gas transport lasers) and thin slabs (diffusion cooled lasers). A third geometry has been developed by the author showing an annular cross section of the light emitting plasma with coaxial electrodes for the supply with electrical power. The latter geometry together with RF excitation and a very fast gas flow for heat dissipation shows an unbeaten beam power capability. The concept of the coaxial laser has been realised at the University of Technology in Vienna and proved to be excellently suited for technological purpose. Moreover a theoretical estimation showed that the latter concept can be extended to a feasible construction of a 100 kW cw laser consisting of 4 plasma modules, each having a diameter of 25 cm and a length of 75 cm. The excitation must be carried out with a 1 Megawatt RF transmitter as it is used in broadcasting. For cooling extra strong blowers are necessary. In the bulk of the paper first the already existing 6 kW coaxial laser will be presented and then the concept for a 100 kW cw carbon dioxide laser will be discussed.