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14 pages, 6764 KiB

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Bismuth-Germanate Glasses: Synthesis, Structure, Luminescence, and Crystallization

by Ksenia Serkina, Irina Stepanova, Aleksandr Pynenkov, Maria Uslamina, Konstantin Nishchev, Kirill Boldyrev, Roman Avetisov and Igor Avetissov

Ceramics 2023, 6(3), 1559-1572; https://doi.org/10.3390/ceramics6030097 - 13 Jul 2023

Cited by 3 | Viewed by 3351

Abstract

Bismuth-germanate glasses, which are well known as a promising active medium for broadband near-infrared spectral range fiber lasers and as an initial matrix for nonlinear optical glass ceramics, have been synthesized in a 5–50 mol% Bi₂O₃ wide concentration range. Their structural and physical characteristics were studied by Raman and FT-IR spectroscopy, differential scanning calorimetry, X-ray diffraction, optical, and luminescence methods. It has been found that the main structural units of glasses are [BiO₆] and [GeO₄]. The growth in bismuth oxide content resulted in an increase in density and refractive index. The spectral and luminescent properties of glasses strongly depended on the amount of bismuth active centers. The maximum intensity of IR luminescence has been achieved for the 5Bi₂O₃-95GeO₂ sample. The heat treatment of glasses resulted in the formation of several crystalline phases, the structure and amount of which depended on the initial glass composition. The main phases were non-linear Bi₂GeO₅ and scintillating Bi₄Ge₃O₁₂. Comparing with the previous papers dealing with bismuth and germanium oxide-based glasses, we enlarge the range of Bi₂O₃ concentration up to 50 mol% and decrease the synthesis temperature from 1300 to 1100 °C. Full article

(This article belongs to the Special Issue Advanced Glasses and Glass-Ceramics)

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11 pages, 3950 KiB

Open AccessArticle

Study of Mid-Infrared Emission and Structural Properties of Heavy Metal Oxide Glass and Optical Fibre Co-Doped with Ho³⁺/Yb³⁺ Ions

by Tomasz Ragin, Agata Baranowska, Marcin Kochanowicz, Jacek Zmojda, Piotr Miluski and Dominik Dorosz

Materials 2019, 12(8), 1238; https://doi.org/10.3390/ma12081238 - 15 Apr 2019

Cited by 15 | Viewed by 3553

Abstract

Bismuth-germanate glasses with low hydroxide content co-doped with Ho³⁺/Yb³⁺ ions have been investigated in terms of structural and spectroscopic properties. To reduce OH^- ions content and improve transmittance value at the wavelength of 3.1 µm, the glass synthesis has been carried out in low vacuum conditions (45–65 mBar). The composition of the host glass based on heavy metal oxides affects the maximum phonon energy (hω_max = 724 cm⁻¹), which low value has a positive impact on the mid-infrared emission parameters. Emission band at the wavelength of 2.87 µm was observed in glass co-doped with mol% 0.25 Ho₂O₃/0.75 Yb₂O₃ under 980 nm high power laser diode wavelength excitation. Lifetime measurements of the Yb³⁺:²F_5/2 quantum level indicate efficient Yb³⁺ → Ho³⁺ energy transfer (η = 61%). The developed active bismuth-germanate glass was used as the core of optical fibre operating in the mid-infrared region. Full article

(This article belongs to the Special Issue Recent Advances on Optical, Structural and Luminescence Properties of Glass and Glass-Ceramics)

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10 pages, 293 KiB

Open AccessArticle

Preparation and Elastic Moduli of Germanate Glass Containing Lead and Bismuth

by Hj A. A. Sidek, Hamid R. Bahari, Mohamed K. Halimah and Wan M. M. Yunus

Int. J. Mol. Sci. 2012, 13(4), 4632-4641; https://doi.org/10.3390/ijms13044632 - 11 Apr 2012

Cited by 18 | Viewed by 6554

Abstract

This paper reports the rapid melt quenching technique preparation for the new family of bismuth-lead germanate glass (BPG) systems in the form of (GeO₂)₆₀–(PbO)_40−x–(½Bi₂O₃)_x where x = 0 to 40 mol%. Their densities with respect of Bi₂O₃ concentration were determined using Archimedes’ method with acetone as a floatation medium. The current experimental data are compared with those of bismuth lead borate (B₂O₃)₂₀–(PbO)_80−x–(Bi₂O₃)_x. The elastic properties of BPG were studied using the ultrasonic pulse-echo technique where both longitudinal and transverse sound wave velocities have been measured in each glass samples at a frequency of 15 MHz and at room temperature. Experimental data shows that all the physical parameters of BPG including density and molar volume, both longitudinal and transverse velocities increase linearly with increasing of Bi₂O₃ content in the germanate glass network. Their elastic moduli such as longitudinal, shear and Young’s also increase linearly with addition of Bi₂O₃ but the bulk modulus did not. The Poisson’s ratio and fractal dimensionality are also found to vary linearly with the Bi₂O₃ concentration. Full article

(This article belongs to the Section Materials Science)

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