High efficiency emission of a laser based on Yb-doped (Lu,Y)2O3 ceramic

We demonstrated highly efficient laser emission of a 6% at. Yb:(Lu,Y)2O3 ceramic sample with formula (Yb0.06Lu0.12Y0.78Zr0.04)2O3 (i.e. Yb doped solid solution of Y2O3 and Lu2O3 with Zirconia as sintering aid) fabricated by means of solid-state sintering of mixed sesquioxide nanoparticles under vacuum. The ceramics features a very good optical quality, with a transmission very close to the theoretical limit. The spectroscopic characteristics were investigated, resulting in intermediate properties between Yb:Y2O3 and Yb:Lu2O3. Laser emission was obtained under diode pumping at 936 nm, in CW and quasi-CW pumping condition. We measured a maximum output power of 3.9 W at 1077 nm while the highest slope efficiency was 51.2%, in quasi-CW regime. In CW, at the same laser wavelength, the output power was 2.2 W with a corresponding slope efficiency of 35.1%. The explored range of tunability, 97 nm, is to the best of our knowledge one of the broadest and continuous intervals measured with Yb-doped materials. Mixed Lu-Y ceramic sesquioxides appear then as a promising laser material for broadly tunable laser sources and, in consequence, for the generation of ultrashort laser pulses.