Calculating Line Intensities of ¹S₀ Emission through Standard and Modified Judd-Ofelt Theories in Pr³⁺-Doped CaAl₁₂O₁₉ and SrAl₁₂O₁₉

A modified Judd-Ofelt theory is used in this paper to treat the electric dipole transitions within the 4f² configuration of Pr³⁺ by considering two main perturbing components of 4f5d and 4fn′g. Through the energy-level calculation and standard tensorial analysis, the explicit distance between the 4f5d configuration and the ¹S₀ state and other lower 4f² energy levels are determined. The rare-earth ion Pr³⁺ substituted at Sr²⁺ sites in SrAl₁₂O ₁₉ (SAO) and Ca²⁺ sites in CaAl₁₂O₁₉ (CAO) has the site symmetry of D_3h. The standard Judd-Ofelt parameters A₃₃², A₃₃⁴, A ₅₃⁴, A₅₃⁶, A₇₃ ⁶ are included in the calculation, together with odd-λ parameters A₃₃³ and A₅₃⁵. The emitting line intensities originating from ¹S₀ and ³P₀ are then calculated. Compared with the experimental measurements, the modified model yields better results than the standard Judd-Ofelt theory.