Calculation of Judd-Ofelt parameters for Er3+ in β-NaYF4: Yb3+, Er3+ from emission intensity ratios and diffuse reflectance spectra

We report the calculation of Er3+ Judd-Ofelt (JO) parameters for β-phase NaYF4:Yb3+, Er3+. The parameters were extracted from measured emission intensity ratios and the diffuse reflectance spectrum, augmented by a single radiative rate constant. The derived parameters were used to calculate the entire suite of radiative rate constants for the f-f transitions of Er3+ in the visible and near infrared (NIR) range and to calculate the absorbance spectrum. Two sets of JO parameter values, in units of pm2, were calculated using two available sets of reduced matrix elements (Ω22.36, Ω40.22, Ω61.24) and (Ω22.43, Ω40.21, Ω61.22).