An optically pumped laser has a gain medium positioned inside of an optical resonator
cavity and disposed about a resonator optical axis. An optical pumping source is
positioned outside of the optical resonator cavity. A reflective coupler with a
coupler body, and an interior volume passing therethrough is positioned proximal
to the optical pumping source. Light from the pumping source passes into an entrance
aperture of the reflective coupler to an exit aperture of the reflective coupler
positioned distal to the optical pumping source. The interior volume of the reflective
coupler is bounded by a reflective surface, an entrance aperture and the exit aperture,
and is substantially transparent to radiation from the optical pumping source.
The reflective surface has a high reflectivity matched to radiation from the optical
pumping source. The reflective coupler directs radiation from the optical pumping
source into the optical resonator cavity and gain medium, conditioning the numerical
aperture and spatial intensity distribution across the exit aperture.