Zig-zag active-mirror laser with cryogenic Yb3+:YAG/YAG composite ceramics

We report on a novel amplifier configuration concept for a 10 kW laser system using a zig-zag optical path based on a cryogenic Yb:YAG Total-Reflection Active-Mirror (TRAM) laser. The laser material is a compact composite ceramic, in which three Yb: YAG TRAMs are combined in series to increase the output power. Output powers of up to 214 W with a slope efficiency of 63% have been demonstrated for CW operation, even at a quite low pump intensity of less than 170 W/cm(2). Further scaling could achieve output powers of more than 10 kW. (C) 2011 Optical Society of America