Enhanced luminescence at 2.7 μm of NaLuF single crystals co-doped Er/Pr grown by Bridgman method.

NaLuF single crystals co-doped with 1 mol. % Er and various concentrations (0.1 mol. %, 0.3 mol. %, 0.5 mol. %, 0.7 mol. %, and 1 mol. %) of Pr were successfully grown using the Bridgman method. Optical spectroscopic investigations of the obtained single crystal were reported for the absorption, emission, and luminous decay. The obtained single crystal appears with almost no absorption at the 2.7 μm band, attributable to the OH bond. According to the Judd-Ofelt (J-O) theory, the J-O intense parameters of Er ions were calculated. Under the 980 nm LD pumping, an obviously enhanced emission at 2.7 μm was obtained in the Er/Pr co-doped crystal compared with the Er singly doped crystal due to the energy transfer from Er to Pr. The most intense emission at 2.7 μm was obtained when the doping concentrations of Er and Pr were 1 mol. % and 0.5 mol. % in the present research. The maximum emission cross-section and gain cross-section at 2.7 μm were also estimated. Moreover, using the Dexter theory, the energy transfer microscopic parameters have been calculated, and the decay curve fitting using the Inokuti-Hirayama expression indicated the dipole-dipole energy transfer from Er to Pr ions.