Fabrication, microstructure and optical properties of Yb:Y3ScAl4O12 transparent ceramics with different doping levels

Transparent Yb:Y3ScAl4O12 (Yb:YSAG) ceramics with different ytterbium doping concentrations such as 5, 10, 15, 20 at.% have been successfully fabricated by solid-state reactive sintering. All the obtained ceramics are in dense and homogeneous structure after sintering at 1820 degrees C for 30 hours and with a posttreatment by hot isostatic pressing at 1750 degrees C for 3 hours with 200 MPa pressure. We systematically analyzed the influence of Yb3+ doping concentration on the microstructure and optical properties of the ceramics. The 10 at.% Yb:Y3ScAl4O12 ceramics with a thickness of 3.2 mm show the best transparency as high as 80.9% at 1100 nm. The laser emission of the 10 at.% Yb:YSAG ceramics was tested, resulting in a maximum slope efficiency of 67.6% and a maximum output power of 11.3 W under quasi-continuous wave pump conditions. The tuning range spanned from 990 to 1071 nm.