UConn Physics Colloquium

High-power laser-diodes (LDs) for materials processing comprise ~25% of the $3-4B market for laser diodes. The main applications are direct diode and optical pumps for Nd:YAG and Yb:YAG solid-state lasers and Yb-doped fiber lasers. Single, broad-area, 100µm wide, broad-area, LDs emit ~12W of optical power whereas 10mm-wide LD bars, with 10% to 80% fill-factor, emit ~5W of optical power per 100µm-wide emitter. These devices operate at the thermal, mechanical and optical limits of the materials used to manufacture the diodes. The thermal power-density is locally 3kW/cm2 for a 4mm cavity-length single-emitter and an average 0.5 kW/cm2 for a 200W, 4mm by 10mm LD-bar. The optical power-density at 12W per 100µm wide emitter is ~12 MW/cm2. The mechanical stresses from CTE mismatch and bending often affect indices of refraction which consequently change modal behavior. This talk will discuss the eclectic knowledge-base required to develop and manufacture reliable, high-performance, high-power laser-diodes.