High-Power Quasi-CW Diode-Pumped 750 nm VECSEL Emitting a Peak Power of 29.6 W and an Average Power of 8.5 W

The spectral range between 700 nm and 800 nm has lately been of increasing interest for several applications e.g. in medicine. State-of-the-art vertical external-cavity surface-emitting lasers (VECSELs) with direct emission in that range are usually pumped using solid-state lasers at 532 nm. They are still limited with respect to the output power [1] , [2] , owing mostly to the large temperature dependence of the electronic and optical material properties and a limited durability. Reducing the quantum defect by in-well pumping proved to strongly diminish thermal effects [3] and using diode lasers in a multi-pass pumping scheme opened the way for further power scaling [4] .