Fluorescence line narrowing and Judd-Ofelt theory analyses of Eu3+-doped low-silica calcium aluminosilicate glass and glass-ceramic

Eu-doped calcium aluminosilicate glass and glass-ceramic were synthesized and studied by site-selective spectroscopy. Using both broadband excitation and fluorescence line narrowing techniques, the D05→F17 emission transition was studied under resonant excitation at different wavelengths within the F07→D05 band. In order to explore the local structure of the systems, crystal-field analysis was applied assuming C2v site symmetry. Moreover, from the emission spectra of glass and glass-ceramic systems, Judd-Ofelt parameters Ωt (t = 2, 4) were considered. Transition probability (A), stimulated emission cross-section (σ), radiative lifetime (τR) and branching ratios (β) due to the transition D05→FJ7 (J = 1, 2, 3 and 4) of Eu3+ ions were evaluated in different local fields and their relative variations were discussed. The crystallization process, which converted the glass into glass-ceramic, promoted an important enhancement in the quantum efficiency, which was improved from 45% to 60%.