Power scaling of narrow-linewidth 2mm GaSb-based semiconductor disk laser

In recent years, optically pumped semiconductor disk lasers (SDLs) have attracted considerable interest, since they deliver simultaneously high output power and excellent beam quality [1]. Recently, the realization of high-performance SDLs based on the (AlGaIn)(AsSb) material system with emission wavelengths ranging from 1.8 to 2.8 m has been reported [2-3]. Room-temperature output powers of up to 4.2 W [4] have been demonstrated recently, making this laser source interesting for direct applications such as medical therapy or materials processing. Further applications in this wavelength regime such as high-resolution spectroscopy, long-range gas sensing, LIDAR and free-space optical data transmission via phase modulation require single-mode narrow-linewidth (kHz range) emission and output powers in the 0.1-1 W range. Higher output powers are a clear benefit since, e.g. in data transmission, fewer, or even no subsequent power amplifier stages will be required. A typical benchmark for amplifier-free airborne communications is 1 W at <100 kHz linewidth.