High power Yb:KGW and Yb:KYW thin disk laser operation

Summary form only given. The Yb/sup 3+/-doped potassium tungstates KY(WO/sub 4/)/sub 2/ (KYW) and KGd(WO/sub 4/)/sub 2/ (KGW) are for several reasons of great interest for diode-pumped solid state lasers. Compared with Yb:YAG, they have a smaller quantum defect of only /spl sim/4% and higher absorption and emission cross sections. Furthermore Yb:KGW and Yb:KYW have a broad emission bandwidth, comparable to that of Yb:glass, which allows for the generation and amplification of ultrashort pulses. With a mode-locked Yb:KGW rod laser, end-pumped by two high brightness diodes, a pulse duration of 176 fs at 1.1 W of average output power has already been demonstrated. For these reasons Yb:KYW and Yb:KGW are very promising candidates both for high power cw and for mode-locked operation in a thin disk laser setup, which has already demonstrated its ability to produce high cw output powers at high efficiencies up to the kW range and fundamental mode operation up to 97 W using Yb:YAG. Moreover, high power mode-locked operation of an Yb:YAG thin disk laser has been obtained with 16.2 W of average output power. In first experiments Yb:KGW and Yb:KYW thin disk lasers have been investigated at high cw output powers both in multimode and fundamental mode operation. Numerical calculations are presented as well as experimental results.