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The thermal and optical properties of 60TeO2-20K2TeO3-10WO3-10Nb2O5 (in mol%) glasses doped with Ho2O3, Er2O3, and Tm2O3 were explored in the present work. The thermal stability, refractive index n, extinction coefficient k, absorption coefficient α, and optical band gap of the glasses were evaluated. The UV–Vis–NIR absorption spectra, the Judd–Ofelt intensity parameter, the spectroscopic quality factor, and the emission and absorption cross-sections were calculated to investigate the effects of Er3+ and Tm3+, respectively, on the band spectroscopic properties of Ho3+ ions. The results showed that the maximum emission cross-section was approximately 8 × 10 − 21   c m 2 , and the values of the full width at half maximum ( F W H M) , quality factor ( σ e × F W H M) , and gain coefficient of Ho3+: 5I7 → 5I8 were also reported. The value of the F W H M × σ e was 1200 × 10 − 28   c m 3 , which showed greater gain characteristics than earlier study results. For 2   μ m mid-infrared solid-state lasers, the glasses that were examined might be a good host material. [ABSTRACT FROM AUTHOR]

In the optical energy gap, visible and near-IR emission of halide phosphate glasses with a composition of 40P2O5-30ZnO-20LiCl-10BaF2 in mol% doped with 3.5 × 104 ppm Pr2O3, referred to as PZLBPr, were synthesized. The UV-VIS-NIR and spectroscopic properties of these glasses were also predicted. The current glasses had broadband emission photoluminescence covering a wavelength range of 1250 to 1700 nm when excited at 455 nm. These bands for near-infrared emission luminescence relate to the transitions 1G4 → 3H5, 1D2 → 1G4, and 3H4 → 3F3, 3F4 in the optical telecommunication window. The significant PL emission wideband was caused by the radiative transition from Pr3+: 1D2 to 1G4. At 445 nm excitation, these glasses exhibited emission bands that corresponded to blue/reddish orange spectral ranges in visible ranges. The prepared glass has a high lasing quality factor (Ω4/Ω6 = 0.9), high optical energy (4.72 eV), and quantum efficiency = 87.3% with FWHM = 156 nm of transition emission from the 1D2 → 1G4 level. As a result, broadband near infrared optical amplifiers can be fabricated from the prepared glasses. [ABSTRACT FROM AUTHOR]

A new glass with a composition of 40P2O5-30ZnO-20LiCl-10BaF2 (in mol%), doped with 3.5Nd2O3-3.5Yb2O3, was fabricated by the quenching melt technique. The luminescence (PL) and gamma spectroscopy of the glass were investigated systematically. The spectroscopic parameters of the prepared glass, such as the optical energy gap, Judd–Ofelt parameters Ωk (where k = 2, 4 and 6), lifetimes and branching ratio of the Nd3+/Yb3+ level, were evaluated. Moreover, the shielding parameters, such as the linear and mass attenuation coefficients, mean free path and half-value layer, were evaluated. The prepared glass had a spectroscopic quality factor (Ω4/Ω6) of 0.84, which is about three-times larger than that of the most standard laser host, Nd3+:YAG. The energy of the 2P1/2 (Nd3+) level (~23,250 cm−1) was twice the energy of the Yb3+ transition (~10,290 cm−1). The value of the emission cross section ( σ e m (λ) ) of Nd3+:4F3/2→4I9/2 and Yb3+:2F5/2→2F7/2 were 2.23 × 10−24 cm2 and 2.88 × 10−24 cm2, respectively. The fabricated glass had a high emission cross section and low mean free path parameters, which makes the fabricated glass a potential candidate for multifunctional applications, such as laser emissions for medical purposes. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports on the spectral results of Dy3+ (1.0mol%) ions-doped TeO2–ZnO–PbO–PbF2–Na2O (TZPPN) glass. Raman spectrum measurements, differential thermal analysis (DTA) profiles of this rare-earth ion-doped glass were carried out. From the DTA thermogram, glass transition (T g ), crystallization (T c ) and melting (T m ) temperatures were evaluated. Direct and indirect optical band gaps were calculated based on the glasses UV absorption spectra. From the absorption spectra, Judd–Ofelt (J–O) intensity parameters, Ω k , were calculated. Using J–O intensity parameters, several radiative properties such as spontaneous transition probabilities (A R ), radiative branching ratios (β R ) and radiative lifetimes (τ R ) were determined for the excitation level 4F9/2. From the emission spectra, a strong yellow emission at 574nm (4F9/2→6H13/2) was observed and it also showed a combination of blue and red emission bands for this glass. The stimulated emission cross-section σ(λ p ) was also evaluated for the 4F9/2→6H J (J=11/2, 13/2, and 15/2) transitions. This study indicates that 1mol% Dy2O3-doped tellurite glass can be considered for white light generation with the excitation of blue light (454nm). [Copyright &y& Elsevier]

Abstract: In this work a transparent bulk glass with the mol% composition 76TeO2·10ZnO·9.0PbO·1.0PbF2·3.0Na2O doped with Tm3+ has been synthesized. Results of differential thermal analysis (DTA) indicate a high thermal stability and low tendency to crystallization of this glass. The refractive indices at different wavelengths, the Urbach energy, the optical energy gap, the Sellmeier gap energy and the dispersion energy have been estimated. Spectroscopic quality factor of Tm3+ was evaluated from optical absorption spectra. Electric and magnetic dipole transition probabilities, branching ratios, and radiative lifetimes of several excited states of Tm3+ have been predicted using calculated intensity Judd–Ofelt parameters. The classical McCumber theory has been applied to evaluate the emission cross-sections for 3F4 → 3H6 transition around 1.8μm. This study shows that TZPPN glass doped with Tm3+ ions is a promising candidate for laser applications. [Copyright &y& Elsevier]

Understanding the atomic structure of glasses is critical for developing new generations of materials with important technical applications. In particular, the local environment of rare-earth ions and their distribution and clustering is of great relevance for applications of rare earth-containing glasses in photonic devices. In this work, the structure of Gd2O3 doped lithium and potassium aluminosilicate glasses is investigated as a function of their network modifier oxide (NMO–Li2O, K2O) to aluminum oxide ratio using molecular dynamics simulations. The applied simulation procedure yields a set of configurations, the so-called inherent structures, of the liquid state slightly above the glass transition temperature. The generation of a large set of inherent structures allows a statistical sampling of the medium-range order of the Gd3+ ions with less computational effort compared to other simulation methods. The resulting medium-range atomic structures of network former and modifier ions are in good agreement with experimental results and simulations of similar glasses. It was found that increasing NMO/Al ratio increases the network modifier coordination number with non-bridging oxygen sites and reduces the overall stability of the network structure. The fraction of non-bridging oxygen sites in the vicinity of Gd3+ ions increases considerably with decreasing field strength and increasing concentration of the network modifier ions. These correlations could be confirmed even if the simulation results of alkaline earth aluminosilicate glasses are added to the analysis. In addition, the structure predictions generally indicate a low driving force for the clustering of Gd3+. Here, network modifier ions of large ionic radii reduce the probability of Gd–O–Gd contacts. [ABSTRACT FROM AUTHOR]

The medium-range atomic structure of magnesium and barium aluminosilicate glasses doped with Gd₂O₃ as a model rare earth oxide is elucidated using molecular dynamics simulations. Our structure models rationalize the strong dependence of the luminescence properties of the glasses on their chemical composition. The simulation procedure used samples' atomic configurations, the so-called inherent structures, characterizing configurations of the liquid state slightly above the glass transition temperature. This yields medium-range atomic structures of network former and modifier ions in good agreement with structure predictions using standard simulated annealing procedures. However, the generation of a large set of inherent structures allows a statistical sampling of the medium-range order of Gd 3+ ions with less computational effort compared to the simulated annealing approach. It is found that the number of Si-bound non-bridging oxygen in the vicinity of Gd 3+ considerably increases with growing ionic radius and concentration of network-modifier ions. In addition, structure predictions indicate a low driving force for clustering of Gd 3+ , yet no precise correlation between the atomic structure and luminescence lifetimes can be conclusively established. However, the structure models provided in this study can serve as a starting point for future quantum mechanical simulations to shed a light on the relation between the atomic structure and optical properties of rare earth doped aluminosilicate glasses.