Quest of athermal solid state laser: case of Yb:CaGdAlO4

Emission of Yb: CALGO is constituted of a broad band lying between 990 nm and 1060 nm with relatively high emission cross section values. Since Yb3+ ions occupy a single crystallographic site, the disorder is related to the surrounding cations presenting different size and cationic charges. Laser experiments were performed on a 2%Yb:CALGO sample with anti-reflection coating using Ti:sapphire pumping at 979 nm. A laser oscillation was obtained in sigma polarization from 1050 to 987.6 nm using non-collinear pumping. Consequently, a quantum defect value as low as 0.8% was obtained. This is one of the smallest values ever reported in the literature. In addition the thermal conductivity values are high (k=6.3 and 6.9 W.m-1.K-1 for the two orientations).