Comparisons of waveguide folding geometries in a CO(2) z-fold laser

In this paper we compare three types of optical arrangement used for folding in a z-fold CO(2) waveguide laser excited by a transverse rf discharge. In particular, we present measured output power as a function of discharge conditions for folded resonators with plane mirrors, curved mirrors, and partial waveguiding. To date the laser has produced a maximum of 53.4 W from 115 cm of discharge, i.e., 0.46 W/cm. The folding losses predicted by scalar diffraction theory agree reasonably well with those derived from a fit between the experimental data and a Rigrod analysis.