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Abstract: Multicomponent lead borate glasses modified by PbX2 (X=F, Cl or Br) were examined. For the first time, lead tungstate PbWO4 crystallites dispersed into glass matrices were successfully obtained from controlled crystallization. Excitation by 310nm line leads to broad blue luminescence related to the radiative transition which occurred in the PbWO4 crystallites. It was found that halogen X ions (X=F, Cl or Br) were also incorporated in the distorted crystal system of PbWO4. It was proved by results obtained from X-ray diffraction as well as luminescence measurements. [Copyright &y& Elsevier]

Abstract: Dysprosium-doped lead borate glasses before and after heat treatment have been studied. Lead tungstate PbWO4 crystallites were identified in lead borate glasses after heat treatment. Luminescence was examined under different excitation wavelengths. Blue luminescence of PbWO4 crystallites embedded in lead borate glass is observed upon 310nm excitation. Luminescence spectra measured under excitation at 390nm consists of two characteristic blue and yellow bands, which correspond to 4F9/2–6H15/2 and 4F9/2–6H13/2 transitions of Dy3+. Blue band is enhanced and broadened in comparison to yellow 4F9/2–6H13/2 transition, when Dy3+ and PbWO4 crystallites in lead borate glass after heat treatment are simultaneously excited by 360nm line. [Copyright &y& Elsevier]

Abstract: Compositional-dependent lead borate glasses doped with transition metal and rare earth ions were studied using absorption and luminescence spectroscopy. The trivalent Cr3+, Eu3+ and Dy3+ ions were used as a spectroscopic probe in glass samples with various PbO/B2O3 ratios. Spectral analysis indicates that Cr3+ ions occupy intermediate field sites; the both sites coexist and emit from the 4T2 (low-field) and the 2E (high-field) states, respectively. The R and Y/B values due to 5D0–7F2/5D0–7F1 and 4F9/2–6H15/2/4F9/2–6H13/2 luminescence intensity ratios of Eu3+ and Dy3+ ions, respectively, increase with increasing heavy metal (PbO) content, suggesting higher asymmetry and more covalent bonding character between rare earth and oxygen ions. [Copyright &y& Elsevier]

Abstract: New multicomponent lead borate based glasses with various PbO/B2O3 weight ratio were prepared. The glass samples were analyzed in detail by using Raman and IR absorption spectroscopy. Optical properties of Eu3+ ions have been investigated in lead borate based systems, in which PbO/B2O3 weight ratios were changed from 1:2 to 8:1 in glass composition. The values of the phonon energy of the host and 5D0 lifetime of Eu3+ decrease, whereas absorption and emission intensities, as well as bonding parameter increase with increasing PbO concentration. Additionally, spectral lines are shifted in direction to the lower frequency region. Non-monotonic dependence of the fluorescence intensity ratio R (5D0–7F2/5D0–7F1) upon PbO/B2O3 content has been observed in contrast to bonding parameter that is also non-linear but monotonic. Some structural and spectroscopic aspects for Eu-doped lead borate based glasses are presented. [Copyright &y& Elsevier]

Thermal, structural and optical properties of Er doped oxyfluoride lead borate glasses in the B2O3-PbF2-PbO-Al2O3-WO3 system have been investigated. Properties of the glasses were analysed as a function of PbF2 concentration. Two multicomponent oxyfluoride systems were examined, where the B2O3:PbO+PbF2 molar ratio was either 3:1 or 4:5. Structural behaviour has been analysed using Raman and infrared spectroscopy in 1500-400 cm-1 spectral region, where characteristic bands related to the B-O vibrations of the borate network are located. Addition of PbO and/or PbF2 to the borate glass results in the creation of trigonal BO3 and tetrahedral BO4 units. Quite intense and long lived near-infrared luminescence of Er3+ ions at 1.55 µm related to the main 4I13/2 → 4I15/2 laser transition has been observed. Thermal and spectroscopic parameters were measured for the 3:1 and 4:5 systems. The glass transition temperature Tg and thermal stability parameters ΔT and H (the Hruby parameter) decrease, whereas luminescence intensity and the 4I13/2 lifetime increase with increasing PbF2 concentration. Based on analysis of luminescence decay curve it was found that in oxyfluoride lead borate based glasses, with a B2O3:PbO+PbF2, molar ratio 4:5 4I13/2 lifetimes of Er3+ ions were longer than in the sample with a 3:1 ratio. [ABSTRACT FROM AUTHOR]

Abstract: Spectroscopic properties of Nd3+ ions in B2O3–PbO–Al2O3–WO3 glasses have been reported. The spectroscopic parameters have been determined from absorption and emission measurements together with Judd–Ofelt analysis. Addition of lead oxide to the borate matrix significantly increases radiative parameters like radiative transition rate, measured lifetime, quantum efficiency and peak stimulated emission cross-sections. Three emission lines at 904, 1061 and 1335nm have been registered in lead borate-based glass, which correspond to the transitions originating from the 4F3/2 level to the 4I9/2, 4I11/2 and 4I13/2 levels of Nd3+ ions, respectively. Quite large room temperature peak stimulated emission cross-section has been obtained for 4F3/2–4I11/2 transition of Nd3+ ions in lead borate based glass, which is promising for NIR laser application at 1061nm. [Copyright &y& Elsevier]

Abstract: The heavy metal fluoride glasses based on InF3 and doped with 2mol% of ErF3 were obtained as amorphous material. In order to obtain glass-ceramics, as-melted samples were annealed at various temperatures and times. The changes of the erbium spectroscopic properties in the multicomponent fluoride system are discussed as a function of thermal treatment. The multi-step mechanism of crystallization has been analyzed by spectroscopic analysis and compared with the differential scanning calorimetry (DSC) and X-ray diffraction (XRD) data. [Copyright &y& Elsevier]

Abstract: Effect of heat treatment on Er3+ containing multicomponent oxyfluoride lead borate glasses in (72− x)PbO–xPbF2–18B2O3–6Al2O3–3WO3–1ErF3 (where x =9 or 72) system have been studied. The samples with low and high PbF2 concentrations were analyzed using X-ray diffraction and luminescence spectroscopy. Several narrowed and relatively intense diffraction lines have been formed after heat treatment attributed to the orthorhombic PbF2 phase. Luminescence spectroscopy revealed bands due to 4I13/2–4I15/2 and 4S3/2–4I15/2 transitions of Er3+ ions. This observation makes these glasses candidates for NIR laser active media and up-conversion applications. [Copyright &y& Elsevier]

Abstract: A heavy metal oxide borate glass with composition (70−x)PbO–18B2O3–6Al2O3–3WO3 (wt%) was modified by variable content of PbF2 (, 36 and 72wt%) and doped with 1wt% of Pr3+ or Tm3+ ions. The influence of the PbF2 content on optical properties and luminescence dynamics has been observed through the variation of an effective line width of 1D2→3H4 and 1G4→3F4 emissions as well as the 1D2 and 1G4 lifetimes of Pr3+ and Tm3+, respectively. It was observed that the increase of PbF2 content leads to narrowing of the 1D2→3H4 band from 680 to 590cm−1. This effect was not observed for the 1G4→3F4 thulium emission. The variation of luminescence kinetics was observed both for Pr3+- and Tm3+-doped samples; the increase of the PbF2 content has changed the 1D2 lifetime from 13.8 to 16.5μs and from 34 to 43μs for the 1G4 level. [Copyright &y& Elsevier]

In this work structural and luminescence properties of gallo-germanate glasses were investigated. The mentioned glass system was modified with barium and antimony oxides and doped with Eu3+ ions. The starting glass consisted of barium oxide as a modifier which was then gradually replaced by antimony oxide to form six glass samples. The gallo-germanate glass as a low-phonon host for RE (Rare Earths) ions is a promising material for optoelectronics. However, luminescence properties closely depend on material composition. For this reason, structural changes in studied materials were induced by changing its chemical composition and the luminescence properties were tested. The FT-IR (Fourier-Transform Infrared Spectroscopy) and the Raman spectra of studied glasses illustrate the tendency to increasing quantity of bridging oxygen connecting germanium ions and decreasing quantity of non-bridging oxygen along with antimony oxide addition. Simultaneously the BP (Boson Peak) measurements and emission spectra of Eu3+ ions show an increasing tendency to the examined glass structure ordering along with modifier oxide addition. [ABSTRACT FROM AUTHOR]

Abstract: A P2O5-CaO-SrO-BaO phosphate glass doped with Tm3+ and glasses doped with (Tm3+, Pr3+) were used for this study. The photo-luminescence behaviors of Tm3+ and Pr3+ in phosphate glass were investigated by absorption, excitation and emission spectroscopy. The energy transfer between Tm3+ and Pr3+ in phosphate glasses (which exhibit a variety of transfer efficiencies) was studied. The experimental quantum efficiencies of the luminescence of Tm3 + η 0 and (Tm3+, Pr3+) doped phosphate glasses were measured to give η/η 0 =0.447, 0.305, and 0.179 for (0.4mol% Pr3+, 1.0mol% Tm3+), (0.8%Pr3+, 1.0%Tm3+) and (1.6mol% Pr3+, 1.0mol% Tm3+), respectively. In order to verify the nature of the ion coupling in our phosphate glass system, we applied the Inokuti–Hirayama model. The non-radiative energy transfer rate from Tm3+ to Pr3+, transfer efficiencies, and the donor–acceptor distance have been calculated and compared with obtained experimental data. As usual, the efficiency and the probability of energy transfer increase with the concentration of the acceptor. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we present the photoluminescence properties of Pr3+, Sm3+ and Er3+ doped phosphate glasses. Optical absorption and emission spectra of lanthanide active ions in P2O5–CaO–SrO–BaO glass have been investigated at room temperature. These glasses have shown strong absorption bands in the near-infrared (NIR) and visible (VIS) region. For Pr3+ doped glass, emission bands centered at 608nm (3P0 → 3H6 + 1D2 − 3H4), 640nm (3P0 → 3F2), 686nm (3P0–3F3) and 723nm (3P0 → 3F4) have been observed with 480nm (3H4 → 3P0) excitation wavelength. Of them, 686nm has shown bright red emission. Emission bands of (4G5/2 → 6H5/2) 560nm, (4G5/2 → 6H7/2) 600nm and (4G5/2 → 6H9/2) 645nm for the Sm3+ phosphate glass, with excitation at (6H5/2 → 4F7/2) 400nm have been recorded. With regard to the Er3+ phosphate glass, a bright fluorescent green–yellow emission at 546nm (4S3/2 → 4I15/2) have been observed. Analysis of decay curves of luminescence revealed occurrence of the strong luminescence quenching originating from the 3P0 metastable level of Pr3+ and 4S3/2 state of Er3+ mainly by a multiphonon relaxation processes to 1D2, 4F9/2 levels respectively. Moreover these results are compared with those obtained by using the Judd–Ofelt theory. According to the Judd–Ofelt theory, the Judd–Ofelt intensity parameters Ω 2,4,6 were calculated, by which the radiative transition probabilities and radiative lifetimes of luminescent levels were obtained. [Copyright &y& Elsevier]

Abstract: Structural behavior and luminescence properties of rare earth ions (Pr3+, Eu3+, Er3+) in oxide and oxyfluoride lead borate glasses have been studied using X-ray diffraction and spectroscopic methods. Substitution of PbO by PbF2 results in decreasing of the number of tetrahedral BO4 units, which was observed for Pr3+ and Eu3+ ions in lead borate glasses using infrared spectroscopy. In contrast to oxyfluoride lead borate glasses, several diffraction lines due to crystalline ErBO3 phase were identified for Er-doped oxide sample. Luminescence spectra for rare earth ions in lead borate based glasses have been analyzed, where PbO was totally substituted by PbF2. [Copyright &y& Elsevier]