High Efficiency Mid-Infrared Laser

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 diode laser array average output power of 400 Watts, is projected to produce over 120 Watts of high quality average output power at either 1u or 2u. The high repetition rate Q-switched output is electronically tunable from 1 to 20 kHz at near constant average power. This spatially configurable output can be used to pump a number of candidate OPO configurations to produce over 30 Watts of high repetition rate, frequency tunable mid-infrared output. This outstanding efficiency is obtained by applying innovative design concepts to the laser crystal and the slab geometry. These concepts enable the application of a laser material with superior optical and thermal characteristics. 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. The concept is directly scalable to the multi-kilowatt fundamental laser average output power range.