High power diode lasers: technology and application in Europe

Abstract

The application field of high power semiconductor lasers is growing rapidly and covers e.g. solid state laser pumping, metal and plastic welding, hard and soft soldering, surface treatment and others. Preferably those applications are attractive, which do not require extremely high beam quality.We have investigated high power diode-laser bars from 808 nm to 980 nm. The scope of this presentation is on focusability and beam quality. For better beam shaping structures with reduced fill factor of 25% to 30% were developed. They were operated in continuous wave operation at power levels of up to 55W. Tests indicate extrapolated lifetimes of more than 100 000 hours at 40W at 980nm cw and about 10 000 hours at 45W -50W at 940nm and 808nm. Monolithicly stacked Nonostacks® were investigated. Operation up to 100°C with excellent lifetimes could be demonstrated.New concepts and applications for low mode number high power diode lasers like tapered laser bars are presented. Examples for various current areas of interest in european research facilities will be given.

Lateral current spreading in stripe laser diodes

“…Quantum well semiconductor laser with its small size, varieties of wavelengths, and high photo-electronic conversion efficiency, has very wide applications [1], [2]. High power semiconductor lasers, including single emitters, laser bars, horizontal bar arrays and vertical bar stacks, have found increased applications in pumping of solid state laser systems for industrial, military and medical applications as well as direct material processing applications such as welding, cutting, and surface treatment [3].…”