Luminescent studies of Dy ion in alkali lead tellurofluoroborate glasses

Dy³⁺-doped alkali lead tellurofluoroborate (RLTB) glasses (R=Li, Na and K) were prepared by melt quenching technique. Judd-Ofelt theory has been used to evaluate the three intensity parameters Ω₂, Ω₄ and Ω₆ from the experimental oscillator strengths. The photoluminescence spectra obtained by the excitation wavelength of 385 nm show four emission bands at 454, 483, 575 and 665 nm corresponding to the ⁴I_15/2→⁶H_15/2 and ⁴F_9/2→⁶H_J/2 (J=15/2, 13/2 and 11/2) transitions, respectively. The laser characteristic parameters like fullwidth at half maxima (FWHM), stimulated emission cross-sections (σ_e), optical gain parameters (σ_e×τ_exp) and gain bandwidth parameters (σ_e×FWHM) were determined. From the visible emission spectra, yellow to blue (Y/B) intensity ratios and chromaticity coordinates were also estimated. The lifetimes of ⁴F_9/2 metastable state were also measured and discussed.