An apparatus and method for achieving a near diffraction-limited, high-average
power output from a solid-state laser oscillator are provided. The solid-state
laser uses multiple disk-shaped laser gain media having a large optical aperture
placed in an unstable resonator. The laser gain media is provided with optical
coatings for operation in the active mirror configuration and is attached to a
rigid, cooled substrate, which allows it to maintain a prescribed shape even when
experiencing significant thermal load. The resonator is configured so as to preferentially
support low order optical modes with transverse dimensions sufficiently large to
efficiently fill the gain media apertures. Resonator configurations capable of
producing standing wave or traveling wave optical fields are disclosed. The resonator
may include means for intracavity correction of an optical phase front by adaptive
optics. Also disclosed is an arrangement of resonator gain elements in axisymmetric
arrays suitable for integration into a compact and lightweight laser system.
