High efficiency Yb:YAG thin disk laser at room and cryogenic temperatures

Yb:YAG thin-disk laser performance at room and cryogenic (80K) temperatures is presented. The Yb: YAG gain media, which is Indium soldered to specialized CuW mounting caps, is cooled using either a pressurized R134A refrigerant system or by a two-phase liquid nitrogen spray boiler. At cryogenic temperatures spontaneous emission measurements reveal sharper transition lines and a decrease in the fluorescence lifetime. Lasing reflects that a true four-level laser. Interchangeable mounting caps allow the same Yb: YAG media to be switched between the two systems. This allows direct comparison of lasing, amplified spontaneous emission, and temperature performance at 15 degrees C and at -200 degrees C.