Optical properties of Dy3+-doped phosphate and fluorophosphate glasses

Optical properties of Dy3+-doped phosphate (P2O5 + K2O + BaO + Al2O3) and fluorophosphate (P2O5 + K2O + BaO + BaF2 + Al2O3) glasses have been investigated. The observed bands in absorption spectra of 1.0 mol% Dy3+-doped glasses have been assigned and analyzed using the parametric free-ion Hamiltonian model. Judd–Ofelt (JO) intensity parameters have been obtained from the optical absorption spectra. The sensitiveness of the Ω2 JO parameter to the hypersensitive transition has been demonstrated. Using these JO parameters radiative properties of some of the excited states of Dy3+ ions have been calculated. A strong yellow emission was observed from the 4F9/2 → 6H13/2 transition of Dy3+ ions in these glasses. The peak stimulated emission cross-section for the 4F9/2 → 6H13/2 transition is found to be comparable with those of other Dy3+: systems. The decay curves of the 4F9/2 level have been measured and are found to deviate from exponential nature with increase in Dy3+ ions concentration. The non-exponential decay curves have been fitted with the Inokuti–Hirayama model which revealed that dipole–dipole mechanism is responsible for the energy transfer processes through Dy3+–Dy3+ interactions.