Spectral properties and 1.55 μm laser operation of Ce3+:Yb3+:Er3+:NaLa(WO4)2 crystal

A series of x at. %Ce3+:10 at. %Yb3+:1 at. %Er3+:NaLa(WO4)2 (x=0,10,…,50) crystal powders were prepared by high temperature solid phase reaction. The effect of Ce3+ concentration on the I411/2→I413/2 transition of Er3+ ions was analyzed. A single crystal of 48 at. %Ce3+:10.4 at. %Yb3+:1.6 at. %Er3+:NaLa(WO4)2 was grown by the Czochralski method. 1.2 W quasicontinuous-wave laser around 1.55 μm was realized when a 2.61 mm thick c-cut slice of the crystal was pumped by a diode laser at 970 nm. The achieved highest slope efficiency was 12.3% and the threshold was 3.8 W.