Active correction of thermal lensing in solid-state lasers. II. Use of a resonator with a controllable configuration

In this paper we describe the design and fabrication of a deformable quartz laser mirror whose lens power can vary within the range ±4 diopters. It is shown experimentally that controlling the resonator configuration of a solid-state laser with a deformable mirror and an apodized output mirror can lead to an axial brightness more than an order of magnitude greater than that of a laser with a plane-parallel resonator, with a concomitant advantage in output power. We find the controllable-resonator configuration that leads to optimum energy output, radiation brightness, and mode selectivity.