Dependence of Judd-Ofelt parameters on overall changing factor of integrated absorption bands of Er3+

Abstract Dependences of Judd-Ofelt (JO) intensity parameters Ωt (t = 2,4,6) and their relative ratios (Ω4/Ω2 and Ω6/Ω2) on overall changing factor (q) of integrated absorption bands of Er3+ have been studied theoretically. These dependences can help us to use relevant method to correctly extract Ωt of a powder material. The study was done by exemplifying the widely studied Er3+ system, which is doped into Gd3Ga5O12, LiNbO3 and SrGdGa3O7 bulk single-crystals and β-NaYF4 crystalline powder. The results show that the Ωt changes linearly with the overall changing factor q: Ωt = γtq + ξt. The linear feature changes from one material to another. The magnetic-dipole oscillator of the 1.5 μm transition results in non-zero nodal increment ξt and hence dramatical changes of the relative ratios Ω4/Ω2 and Ω6/Ω2 (with q) in smaller q region. The dramatical feature limits application of the relevant method for Ωt calibration of a luminescent powder. To get the precise Ωt values using the relevant method, the q value must be large enough. This can be realized by adopting a thin powder plate with a low Er3+ concentration for spectral measurement.