Herriott cell resonators for large area gas discharge lasers

Recent developments in RF excitation of gas discharge lasers have shown that the output power can be area scaled through the use of annular or planar formats, rather than the more conventional length scaling which has characterised diffusion-cooled lasers until now. For CO₂ lasers, this holds the promise of new types of compact lasers with a range of applications in industry and elsewhere, which use novel resonators to extract good quality beams from the unconventional, large area gain geometry. Here we present an analysis of one such resonator, which consists of a spherical mirror Herriott cell enclosed by a Fabry Perot resonator. Optical system parameters are configured for coupling to an annular discharge and results given for both a passive cavity and for its operation when coupled to a large area CO₂ discharge.