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Near-infrared luminescence properties of Nd 3+ and Ho 3+ ions in barium gallo-germanate glasses have been reported. Several spectroscopic parameters for Nd 3+ and Ho 3+ ions have been determined from the Judd-Ofelt analysis and absorption/luminescence measurements. Quite large luminescence lifetime, quantum efficiency and stimulated emission cross-section have been obtained for the main 4 F 3/2  →  4 I 11/2 (Nd 3+ ) and 5 I 7  →  5 I 8 (Ho 3+ ) laser transitions of rare earths in barium gallo-germanate glasses. It suggests that barium gallo-germanate glass is promising for near-infrared laser application at emission wavelengths 1064 nm (Nd 3+ ) and 2020 nm (Ho 3+ ). [ABSTRACT FROM AUTHOR]

Spectroscopic properties of rare earths in lead-free oxyfluoride germanate glasses were studied. The absorption and luminescence spectra of Eu 3+ , Pr 3+ and Er 3+ ions were examined as a function of BaF 2 concentration and several spectroscopic parameters for rare earths were determined. The ratio of integrated luminescence intensity of the 5 D 0 → 7 F 2 transition to that of the 5 D 0 → 7 F 1 transition of Eu 3+ decrease significantly with increasing BaF 2 content. The absorption (Er 3+ ) and emission (Pr 3+ ) ‘hypersensitive transitions’ of rare earths are shifted in direction to shorter wavelengths with increasing BaF 2 content in glass composition. Emission spectra and their decays corresponding to the main 4 I 13/2 → 4 I 15/2 laser transition of Er 3+ were also analyzed. Quite long-lived NIR luminescence of Er 3+ is observed for lead-free glass samples with low BaF 2 concentration. [ABSTRACT FROM AUTHOR]

Highlights: [•] Spectroscopic properties of rare earth doubly doped lead borate glasses were investigated. [•] Luminescence of Tb3+ was successfully detected under excitation of Dy3+. [•] Luminescence of Eu3+ was successfully detected under excitation of Tb3+. [•] The energy transfer processes between rare earth ions in lead borate glass were evidenced. [Copyright &y& Elsevier]

Abstract: Visible luminescence of Dy3+ ions in oxyhalide lead borate glasses was examined. Luminescence spectra show two intense bands at 480nm and 573nm due to 4F9/2 → 6H15/2 (blue) and 4F9/2 → 6H13/2 (yellow) transitions of Dy3+. Luminescence decays from 4F9/2 state and yellow-to-blue luminescence intensity ratios (Y/B) were analysed with PbX2 (X=F, Cl) content. An introduction of PbX2 to the borate glass results in the increasing of 4F9/2 lifetime and the decreasing of yellow-to-blue luminescence intensity ratio, which is due to reduction of covalency between Dy3+ and O2−/X− ions. [Copyright &y& Elsevier]

Lead borate glasses singly and doubly doped with Tm 3+ and Dy 3+ were prepared by traditional melt-quenching technique. The emission spectra of rare earths in studied glass systems were registered under different excitation wavelengths. The observed emission bands are located in the visible spectral region. They correspond to 1 D 2 → 3 F 4 (blue) and 1 G 4 → 3 H 6 (blue) transitions of Tm 3+ as well as 4 F 9/2 → 6 H 15/2 (blue), 4 F 9/2 → 6 H 13/2 (yellow) and 4 F 9/2 → 6 H 11/2 (red) transitions of Dy 3+ . Moreover, the energy transfer process from Tm 3+ to Dy 3+ was observed. The luminescence bands originating to characteristic transitions of thulium and dysprosium ions are present on emission spectra under direct excitation of Tm 3+ . Luminescence lifetimes for the excited states of Tm 3+ and Dy 3+ ions in lead borate glass were also determined based on decay measurements. The luminescence intensities and lifetimes depend significantly on the relative concentrations of the optically active dopants. [ABSTRACT FROM AUTHOR]

In the paper analysis of structural and luminescent properties of antimony-germanate-borate glasses and glass fiber co-doped with 0.6AgNO 3 /0.2Eu 2 O 3 are presented. Heat treatment of the fabricated glass and optical fiber (400 °C, 12 h) enabled to obtain Ag nanoparticles (NPs) with average size 30–50 nm on their surface. It has been proofed that silver ions migrate to the glass surface, where they are reduced to Ag 0 nanoparticles. Simultaneously, FTIR analysis showed that heat treatment of the glass and optical fiber increases the local symmetry of the Eu 3+ site. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lead-free borate glasses singly doped with Dy3+ were synthesized. • Influence of glass formers and glass modifiers on spectral properties were examined. • Local asymmetry around Dy3+ ions increases when content of GeO 2 in glass is changed. • The increasing concentration of fluoride glass modifiers caused decreasing of Y/B. • Our systems exhibit visible luminescence and may be prospective yellowish emitters. Spectral properties of lead-free glasses doped with Dy3+ ions in function of glass formers and glass modifiers were studied. The glass systems in a function of concentration GeO 2 and CaO/SrO/BaO which was partially or totally replaced by CaF 2 /SrF 2 /BaF 2 were synthesized. The visible luminescence spectra for obtained glasses were registered and value of parameters such as ratio of yellow-to-blue luminescence and the Commission Internationale de I'Eclairage (CIE) chromaticity coordinates (x, y) were analyzed in detail. The Y/B increase from 2.97 to 3.8 in systems with increasing of concentration glass former (GeO 2), whereas ratio Y/B slightly decreases when the of content fluoride glass modifiers increases. The obtained results confirm that impact on visible luminescence of lead-free borate glasses doped with Dy3+ ions is greater for glass former than glass modifier. Moreover, studied systems can be used for optoelectronic as yellowish emitters. [ABSTRACT FROM AUTHOR]