Performance of an unstable oscillator on a 30-kW CW gas dynamic laser

Mode-control experiments at a 30-kW CW power level with an unstable resonator at a high Fresnel number were performed on a gas dynamic laser. Near- and far-field intensity distributions were obtained that are consistent with theoretical values for an approximately twice diffraction-limited beam. Under these conditions, the output power was more than half of the maximum multi-mode power.