Spectroscopic and lasing studies of Ce³⁺:Er³⁺:Yb³⁺:YVO₄ crystals

Absorption and fluorescence spectra and fluorescence lifetime measurements are presented for Ce³⁺:Er³⁺:Yb³⁺:YVO₄ crystals and compared to the corresponding data for Er³⁺:Yb³⁺:YVO₄ crystals. These results show that doping with Ce³⁺ ions reduces the lifetime of the ⁴I_11/2 state 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⁺:YVO₄ crystals 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.