The bulk crystal growth, spectral analyses and rate equation model of Yb,Er:SrLaGa₃O₇ crystal

Yb³⁺ and Er³⁺ co-doped SrLaGa₃O₇ (abbr. as Yb,Er: SLGO) bulk crystal with dimensions of Φ 20×30 mm was grown successfully by the Czochralski (Cz) method. The absorption and fluorescence spectra as well as the fluorescence decay curves of Yb,Er: SLGO crystal were measured and investigated. The emission cross-section and fluorescence lifetimes have been obtained at the ~2.7 µm wavelength. Based on Yb³⁺-Er³⁺ energy level diagrams, the rate equation model was built and discussed. It is found that 2.7–3.0 µm emission has been improved in Yb,Er: SLGO crystal under excitation of 980 nm, owing to the sensitization of the co-dopant Yb³⁺ and the resonant energy transfer from Yb³⁺ to Er³⁺. A noteworthy result is that Yb,Er: SLGO crystal is an excellent mid-infrared laser gain material. - Graphical abstract: The bulk crystal of 5 at% Yb³⁺ and 20 at% Er³⁺ co-doped SrLaGa₃O₇ was grown successfully by the Czochralski method. The spectroscopic properties and the rate equation model were presented and analyzed systematically.