First Identification of Rare-Earth Oxide Nucleation in Chalcogenide Glasses and Implications for Fabrication of Mid-Infrared Active Fibers

Authors

  • Zhuoqi Tang,

    1. Mid-Infrared Photonics Group, Faculty of Engineering, University of Nottingham, Nottingham, UK
    2. George Green Institute for Electromagnetics Research, Faculty of Engineering, University of Nottingham, Nottingham, UK
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  • David Furniss,

    1. Mid-Infrared Photonics Group, Faculty of Engineering, University of Nottingham, Nottingham, UK
    2. George Green Institute for Electromagnetics Research, Faculty of Engineering, University of Nottingham, Nottingham, UK
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  • Michael Fay,

    1. Nottingham Nanoscience and Nanotechnology Centre, Faculty of Engineering, University of Nottingham, Nottingham, UK
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  • Nigel C. Neate,

    1. Wolfson Centre for Advanced Materials, Faculty of Engineering, University of Nottingham, Nottingham, UK
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  • Yin Cheng,

    Corresponding author
    1. College of Physics and Electronic Science, Changsha University of Science & Technology, Changsha, China
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  • Emma Barney,

    1. Mid-Infrared Photonics Group, Faculty of Engineering, University of Nottingham, Nottingham, UK
    2. George Green Institute for Electromagnetics Research, Faculty of Engineering, University of Nottingham, Nottingham, UK
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  • Lukasz Sojka,

    1. George Green Institute for Electromagnetics Research, Faculty of Engineering, University of Nottingham, Nottingham, UK
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  • Slawomir Sujecki,

    1. George Green Institute for Electromagnetics Research, Faculty of Engineering, University of Nottingham, Nottingham, UK
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  • Trevor M. Benson,

    1. George Green Institute for Electromagnetics Research, Faculty of Engineering, University of Nottingham, Nottingham, UK
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  • Angela B. Seddon

    Corresponding author
    1. Mid-Infrared Photonics Group, Faculty of Engineering, University of Nottingham, Nottingham, UK
    2. George Green Institute for Electromagnetics Research, Faculty of Engineering, University of Nottingham, Nottingham, UK
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Abstract

Gallium (Ga) helps solubilize rare-earth ions in chalcogenide glasses, but has been found to form the dominant crystallizing selenide phase in bulk glass in our previous work. Here, the crystallization behavior is compared of as-annealed 0–3000 ppmw Dy3+-doped Ge–As–Ga–Se glasses with different Ga levels: Ge16.5As(19−x)GaxSe64.5 (at.%), for x = 3 and 10, named Ga3 and Ga10 glass series, respectively. X-ray diffraction and high-resolution transmission electron microscopy are employed to examine crystals in the bulk of the as-prepared glasses, and the crystalline phase is proved to be the same: Ge-modified, face centered cubic α-Ga2Se3. Light scattering of polished glass samples is monitored using Fourier transform spectroscopy. When Ga is decreased from 10 to 3 at.%, the bulk crystallization is dramatically reduced and the optical scattering loss decreases. Surface defects, with a rough topology observed for both series of as-prepared chalcogenide glasses, are demonstrated to comprise Dy, Si, and [O]. For the first time, evidence for the proposed nucleation agent Dy2O3 is found inside the bulk of as-prepared glass. This is an important result because rare-earth ions bound in a high phonon–energy oxide local environment are, as a consequence, inactive mid-infrared fluorophores because they undergo preferential nonradiative decay of excited states.

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