Continuous Wave Mid Infrared Laser Sources

significant technical issues with current mid-infrared, mid-power solid state laser concepts are low efficiency and limited scalability. The unique concept proposed here utilizes a single mini-slab of rare earth doped YAG which, when pumped with an average diode power of 400 Watts, is projected to produce over 120 Watts of output power at either 1u or 2u. Efficient pump absorption is obtained through a proprietary multi-pass geometry in a low Fresnel number mini-slab, which provides superior, low loss, mode control and a projected beam quality <2x the diffraction limit. When coupled to a novel OPO design, this output can pump a number of candidate OPO materials to produce over 30 Watts of continuous wave, tunable mid-infrared output. This outstanding efficiency is obtained by applying innovative design concepts to the laser crystal, the slab geometry, and the OPO cavity. These concepts simultaneously improve overall nonlinear conversion efficiency and enable operation at pump powers significantly below that of conventional OPO's, thereby minimizing the potential for damage in the nonlinear medium. The system concept is cascadable to several down conversion stages in series, and is directly scalable to the multi-kilowatt fundamental laser average output power range.