Habich, U.U.HabichHeursch, A.A.HeurschPlum, H.-D.H.-D.PlumPoprawe, R.R.Poprawe2022-03-092022-03-091998https://publica.fraunhofer.de/handle/publica/330147A diffusion-cooled CO2-laser with an output power of 1.5 kW was developed and set up with a coaxial RF-excited discharge. The laser beam is extracted by a resonator with helical mirrors, which is stable in the radial direction and unstable in the azimuthal direction. Without any beam transformation this laser emits a general astigmatic beam with an elliptical power density distribution, which is rotating in a plane perpendicular to the beam axis while propagating. Also, the beam shows hard edge diffraction effects due to the hybrid unstable/stable design of the resonator. In order to make the beam applicable to standard materials processing applications a beam shaping device has to be used to transform the general astigmatic beam into one of more rotational symmetry. The resulting beam has a times-diffraction-limited factor M2=1.5.enaberrationcarbon compoundsgas laserlaser beamlaser cavity resonatorlaser material processinglaser mirrorlaser stabilitylight diffractionring laser621conference paper