Efficient Yb3+ sensitized Er3+ emission of Bi2ZnOB2O6:Yb3+/Er3+ single crystal

Highlights: • Bi₂ZnOB₂O₆:Yb³⁺/Er³⁺ single crystal was grown by means of the Kyropoulos method. • μ-Raman investigation showed the low phonon energy of Bi₂ZnOB₂O₆ host matrix. • the 1532 nm emission of Bi₂ZnOB₂O₆:Yb³⁺/Er³⁺ was efficiently excited at 980 nm. • the kinetics of Bi₂ZnOB₂O₆:Yb³⁺/Er³⁺ fluorescence was analyzed using the Inokuti - Hirayama model. -- Abstract: Bi₂ZnOB₂O₆ single crystals doped with Er³⁺and Yb³⁺ ions were grown by means of the Kyropoulos method. Bi₂ZnOB₂O₆:Yb³⁺/Er³⁺ crystals were characterized by high values of nonlinear optical coefficients as well as efficient luminesce of Er³⁺ ions. The structure, vibrational and luminescent properties of Bi₂ZnOB₂O₆:Yb³⁺/Er³⁺ crystals were investigated for the first time. The Raman investigation showed the low phonon energy of Bi₂ZnOB₂O₆ host matrix associated to the vibrations of BO₃, BO₄, ZnO₄ and BiO₆ molecular groups, which allow effective phonon assisted energy transfer between Yb³⁺ and Er³⁺ ions. The 1532 nm emission of Bi₂ZnOB₂O₆:Yb³⁺/Er³⁺ crystals, associated with the ⁴I_13/2 → ⁴I_15/2 transition of Er³⁺ ions, was excited at 380 (by Bi³⁺ ions), 488 (by Er³⁺ ions) and 980 nm (by Yb³⁺ ions) and efficient Yb³⁺ sensitization of Er³⁺ emission was observed. Moreover, the longest decay lifetime equal to 1.36 ms of Er³⁺ emission at 1532 nm was observed for Bi₂ZnOB₂O₆:Yb³⁺/Er³⁺ crystals under 980 nm excitation. Additionally, using the Inokuti - Hirayama model, the kinetics of the fluorescence intensity was analyzed, besides, the energy transfer micro-parameter C_DA and the energy transfer rate parameter W_DA were determined for Bi₂ZnOB₂O₆:Yb³⁺/Er³⁺ crystals. The results indicate a great potential of new multifunctional Bi₂ZnOB₂O₆:Yb³⁺/Er³⁺ crystals for application in the integrated new-generation laser devices.