We report on spectroscopic investigations of the mixed sesquioxide laser materials Yb:LuScO3, Yb:YScO3, and Yb:(Lu,Y,Sc)2O3 as well as mode-locked thin disk laser experiments with Yb:LuScO3 and Yb:(Lu,Y,Sc)2O3. The disordered crystal structures of these materials result in significantly broader emission spectra than for the pure sesquioxides Yb:Sc2O3, Yb:Y2O3, and Yb:Lu2O3 providing a high potential for ultrashort pulse generation. In SESAM mode-locked thin disk laser experiments, pulse durations of around 100 fs could be obtained exploiting >70 % of the gain bandwidth which is to the best of our knowledge the optimum obtained so far for the mode-locked lasers in this setup.
Wepresent first results in applying the thin-disk concept to lasers directly emitting in the visible spectral range. The pump light was provided by 24 InGaN laser diodes emitting 1Weach at 444 nm, which were coupled into a 200 μm fiber. A 300 μm thin Pr3?,Mg2?:SrAl12O19 crystal served as gain medium. In continuous-wave operation an output power of 0.88 W and a slope efficiency of 12% with respect to the absorbed pump power were achieved at an emission wavelength of 643.5 nm. Modulating the pump source at a duty cycle of 10% yielded an instantaneous output power of 1.67 W, corresponding to a slope efficiency of 26%.