Image Number 2 for United States Patent #6834067.
An optically-pumped laser having a gain medium configured to provide a low loss, three-dimensional integrated optical pump cavity that substantially confines optical pump radiation within the lasing volume, which is particularly useful for efficiently pumping solid state gain media that has low pump dopant concentration. The integrated pump cavity includes a plurality of boundaries contiguous with the gain medium. An optical pump source such as a laser diode array supplies optical pump radiation that is input into the gain medium through one or more pump cavity windows with a propagation direction transverse to a laser axis defined through the gain medium. In some embodiments, an optical surface is situated opposite the window to approximately recollimate the input pump radiation. The optical pump cavity may be designed to concentrate the optical pump radiation and approximately uniformly pump the entire volume of the lasing medium. In one such embodiment, the pump cavity includes opposing converging surfaces that concentrate the optical pump radiation as it projects along the laser axis. Embodiments are disclosed in which a solid state gain medium has coatings that operate to suppress amplified spontaneous emission ("ASE"). Some embodiments also include heat sinks that directly contact the transverse boundaries and control the temperature distribution within the gain medium in a predetermined manner.