Fluorescence line-narrowing spectroscopy of a sodium phosphotantalate glass doped with Eu3+

Abstract A new sodium phosphotantalate glass of molar composition 4.4Na2B4O7-84.3NaPO3-10.8Ta2O5-0.5Eu2O3 was studied using laser-induced fluorescence line-narrowing techniques. From the site-selective luminescence spectra of Eu3+ at 77 K, the energies of the Stark components of the 7F1 and 7F2 multiplets were obtained and a crystal-field analysis was carried out assuming a C 2v site symmetry. The dependence of the crystal-field parameters B kq on the excitation energy is similar to that observed in other oxide glasses. The behaviour of the crystal-field ratios B 22/B 20 and B 44/B 40 agrees reasonably well with the values calculated using the geometric model proposed by Brecher and Riseberg and with previous observations made for different metaphosphate glasses. On the other hand, the crystal-field strength parameter 5 is distinctly lower than for these glasses.