Absorption and luminescence spectral analysis of Dy3+-doped magnesium borate glass

This paper reports the luminescence potential of the dysprosium ion (Dy³⁺)-doped (varying contents from 0.1 to 1.0 mol%) magnesium borate glasses prepared by the melt-quenching method. As-quenched samples were characterized systematically to determine the effects of various Dy³⁺ contents on their structure, physical and optical traits. The Judd−Ofelt (J−O) intensity parameters (Ω₂, Ω₄, Ω₆) and radiative properties of the best sample (with 0.7 mol% of Dy³⁺ doping) was evaluated to complement the experimental optical data. The studied glasses revealed three luminescence emission peaks at 382 nm (⁴F_9/2→⁶H_15/2, intense Blue), 572 nm (⁴F_9/2→⁶H_15/2, intense Yellow) and 661 nm (⁴F_9/2→⁶H_11/2, weak Red) under the excitation wavelength of 347 nm. The emission intensity was first increased up to the Dy³⁺ content of 0.7 mol% and then quenched. The observed luminescence intensity quenching was due to the resonant energy transfer from the excited state to the neighbouring ground state of Dy³⁺. The obtained high value of Ω₂ signified the strong degree of covalency between the Dy³⁺ and ligand environment. The optimum glass sample (with 0.7 mol% of Dy³⁺) showed higher values of the branching ratio and stimulated emission cross-cross section for the ⁴F_9/2→⁶H_15/2 (yellow) emission transition, indicating its potential as bright yellow luminescent material and high gain visible laser applications.