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Er3+‐doped fluoride glass and fiber have been widely used in multiple fields such as mid‐infrared laser, visible laser, and amplifier. However, there is no unified conclusion on the thermal and optical properties with respect to varying concentrations of Er3+ doping. Furthermore, this is a paucity of systematic guidance on the preparation of Er3+‐doped fluoride glass and fiber. In this study, fluorozirconate fiberglass with Er3+ doping is systematically examined. Additionally, a preliminary explanation of the evolutionary behavior of glass devitrification, thermal properties, and fluorescence properties is provided. Energy transition models were built for 1.5 and 2.7 µm emissions in Er3+‐doped fluorozirconate at room temperature. Moreover, a suitable doping concentration is proposed based on the evolutionary behavior of thermal and optical properties. In this study, guidance on appropriate Er3+ doping concentration levels in fluorozirconate glass is provided and potential applications are explored. [ABSTRACT FROM AUTHOR]

Fluoride glass is considered as an excellent optical material owing to its ultralow phonon energy (578 cm−1). However, its high thermal expansion coefficient (15.87 × 10−6/K) and deformability severely limit applications under service environments with high temperature, high humidity, and high‐power irradiation. To overcome these limitations, we developed a ZBLAN‐based fluoride glass ceramics (CZBLAN GCs) contained the negative thermal expansion material‐CaZrF6 crystals by phase‐separation engineering. The ability to control the precipitation of the desired crystal phase was achieved by adequate compositional design for phase separation, yielding improved or new properties in the development of fluoride GCs. With the successful precipitation of very uniformly dispersed single CaZrF6 crystals in the glass phase (up to ∼40% crystallinity), a significantly lower thermal expansion coefficient (3.66 × 10−6/K) in the fluoride system was achieved. Moreover, enhanced fluorescence properties of Eu‐doped CZBLAN GCs were observed compared with those of Eu‐doped ZBLAN glass owing to the lower phonon energy in GCs. [ABSTRACT FROM AUTHOR]

Fluoindinate glass (FIG) is considered an ideal material for fiber laser devices and mid‐infrared bulk optics components owing to its ultra‐low phonon energy and broad transparency window. However, the heat generated by devices fabricated with FIG during their operation limits its application. Therefore, there is an urgent need to study its high‐temperature properties. In this study, the thermal properties, microstructure, crystal phase behaviors, and optical and luminescent properties of high‐temperature FIG were comprehensively evaluated. We also attempted to reveal the changes in its structure at high temperatures using variable‐temperature Raman spectroscopy. We first found that the stretching vibration intensity of nonbridging F(Fnb) decreases, and the bending vibration of FIG increases with an increase in temperature, indicating that high temperatures could lead to the fracture of bridge bonds between some [InF6]3− octahedrons. Certainly, this will lead to glass structural instability, which will further increase the tendency of FIG to undergo devitrification in high‐temperature conditions. We believe that this work will provide a reference for the performance improvement and application of fluoride glass at high temperatures. [ABSTRACT FROM AUTHOR]

• Phase-separation engineering in fluoride glass was developed. • A novel transparent Er3+-doped ZnZrF 6 -Ba 6 Zn 7 F 26 perfluorinate glass ceramic was obtained. • The sample exhibits low phonon energy (564 cm−1), ultra-wide transmission range (0.33–8.2 μm, T ≥ 50 %), and strong infrared emission. Perfluorinate glass ceramics with ultra-low phonon energy are very important optical and photonic materials. Unfortunately, there is no suitable method to obtain transparent perfluorinate glass ceramics due to poor thermal stability of fluoride glass. As a result, wide applications of glass ceramics in advanced infrared systems are restricted. Here, an effective method based on phase-separation engineering is used to develop transparent perfluorinate glass ceramics. In this article, a novel transparent Er3+-doped ZnZrF 6 -Ba 6 Zn 7 F 26 perfluorinate glass ceramic was designed and fabricated by phase-separation engineering. The sample exhibits low phonon energy (564 cm−1), ultra-wide transmission range (0.33–8.2 μm, T ≥ 50 %), and strong infrared emission, which is better than that of ZBLAN glass, oxide-, and oxyfluoride-glass ceramics. These good properties of the perfluorinate glass ceramic demonstrate that phase-separation engineering not only offers an effective approach to obtain perfluorinate glass ceramics but also provides wide-ranging opportunities for advanced infrared optical and photonic materials. [ABSTRACT FROM AUTHOR]

Abstract The effect of chloride ions on the properties of Er3+-doped fluorozirconate glass is systematically studied. We first observed a nonlinear mutation of the glass-forming abilities and fluorescence properties of glass when 1 mol% fluoride ions were replaced by chloride ions. The results differed from previous reports. In order to explain this special phenomenon, we investigated the changes of the structure and the Judd-Ofelt theory of glass before and after halogen anion substitution. The results indicate that part of the fluorozirconium octahedral network was destroyed and transformed into a chain structure due to the bridging chlorine atoms, of which the electronegativity is lower than F-. With the increase of Cl-, the glass-forming abilities gradually recovered due to the decrease of the liquid's temperature. Therefore, a non-linear mutation of the glass-forming abilities was exhibited. Furthermore, the predictor χ, the ratio between the Judd–Ofelt parameters Ω 4 and Ω 6 , and the reduction in phonon density caused a mutation on the fluorescence properties of glass, such as the intensity and lifetime. This research could provide a new reference for the anion modification of fluoride glass. [ABSTRACT FROM AUTHOR]

The glass-forming ability of Er3+-doped fluorozirconate glasses was systematically investigated by replacing Na+ ions by Li+ ions. As Li+ content increased, the glass-forming ability showed an approximate Gaussian distribution, and an optimal thermal stability was obtained with the dopant of 5 mol% Li+. The mechanism for the enhancement of glass-forming ability in fluoride glasses upon partial substitution of Li+ ions was preliminarily investigated. Moreover, an Er3+-doped fluorozirconate glass modified by 5 mol% Li+ exhibited stronger fluorescence than the unmodified original glass. The results provided a suitable approach for fluoride glass modification. [ABSTRACT FROM AUTHOR]