Spectroscopic and lasing studies of Ce³⁺:Er³⁺:Yb³⁺:YVO₄crystals

Absorption and fluorescence spectra and fluorescence lifetime measurements are presented for Ce3+:Er3+:Yb3+:YVO4crystals and compared to the corresponding data for Er3+:Yb3+:YVO4crystals. These results show that doping with Ce3+ions reduces the lifetime of the4I11/2state of Er3+and thereby both suppresses upconversion from this state and improves the energy transfer efficiency from Yb3+to Er3+. Lasing from this material is also demonstrated for this first time, both in quasi-continuous wave (QCW) and Q-switched modes. To obtain laser action at ~1.5 μm, the Ce3+:Er3+:Yb3+:YVO4crystals were pumped by laser diodes operating at ~0.98 μm. For QCW operation, a slope efficiency of 2.6% and a threshold of 12 W were obtained. Q-switched pulses of 27 μJ energy and 52 μs pulse to pulse duration were also measured. KGaA.