Judd-Ofelt calculations for spectroscopic characteristics of Dy3+-activated strontium magnesium borate glass

Abstract

Some new type of strontium magnesium borate glass system doped with Dy3+ (various contents 0.1, 0.3, 0.5, 0.7 and 1.0 mol%) were produced using the conventional melt-quenching. Obtained glasses were thermally stable, highly transparent, and moisture resistant. As-prepared samples were characterized to determine their spectroscopic traits. The Judd-Ofelt (J-O) intensity Ωλ (λ = 2, 4, 6) and radiative parameters were calculated to validate the experimental results on the optical characteristics. The XRD pattern of the as-quenched samples verified their glassy nature, FESEM images showed uniform textures and EDX analyses detected the presence of appropriate constituents in the host matrix. Glass containing 0.7 mol% of Dy3+ revealed the optimum optical traits where the luminescence emission intensity was attenuated beyond this content. The optical gain for two intense emission transitions (4F9/2→6H15/2 and 4F9/2→6H13/2) was evaluated. The values of Ωλ (λ = 2, 4, 6) determined the ionic nature of the bonding and symmetry environment of the Dy―ligand matrix based on the viscosity and rigidity of the host glass. The 6H15/2→6F11/2 transition was hypersensitive. The ratio of the yellow to blue (Y/B) emission intensity less than unity indicated the lower degree of covalence between Dy3+ and O2− ions thereby makes these glasses effective for the near UV―LEDs. The higher values of the branching ratio (≥ 50 %) and stimulated emission cross-section enabled the proposed glass composition potential for the optical amplifiers and fibres fabrication. The resonant energy transfer and cross-relaxation processes in the Dy3+ were attributed to be responsible for the improved optical features.