Diode-pumped laser with funnel-coupled pump source

A method of optically pumping a gain medium, comprising:

• conditioning a fluence of an optical pump source beam with a reflective coupler prior to illuminating a gain medium with the optical pump source beam;
• conditioning an angular divergence or numerical aperture of an optical pump source beam with a reflective coupler prior to illuminating a gain medium with the optical pump source beam;
• and
• conditioning a spatial intensity distribution of an optical pump source beam with a reflective coupler prior to illuminating a gain medium with the optical pump source beam.

An optically pumped laser apparatus, comprising:

• at least two reflectors defining an optical resonator cavity and an optical axis;
• a gain medium positioned inside of the optical resonator cavity, disposed about the optical axis;
• an optical pumping source positioned outside of the optical resonator cavity;
• a reflective coupler with a coupler body and an interior volume passing therethrough, the interior volume bounded by a reflective surface, an entrance aperture and an exit aperture, the interior volume being substantially transparent to radiation from the optical pumping source, the reflective surface having a high reflectivity matched to radiation from the optical pumping source, the entrance aperture positioned proximal to the optical pumping source and the exit aperture positioned distal to the optical pumping source, the reflective coupler directing radiation from the optical pumping source into the optical resonator cavity and gain medium with a controllable numerical aperture and spatial intensity distribution across the exit aperture, and the length of the reflective coupler is optimized to provide a smooth intensity profile of minimized numerical aperture and a high transmission.