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1.
The microhardness of chalcogenide glasses (ChGs) of the Sn–Sb–Se (SSS) ternary system was investigated, and the correlation of microhardness with the mean coordination number of the SSS ChGs was determined. To prepare infrared-transparent SSS glass-ceramics (GCs), two SSS ChGs (A, Sn6.23Sb14.11Se79.66; B, Sn9.8Sb17.22Se72.98; by molar composition) were selected and thermally treated at 433 and 448 K, respectively. The improved microhardness (with values that increased by 11.5% and 7.3% for SSS ChG A and B, respectively) of the resulting SSS GCs is attributed to the formation of Sb2Se3 nanocrystals.  相似文献   

2.
Cooperative upconversion luminescence (CUCL) occurs in spectral regions in which single ions do not have energy levels. However, all results reported so far are concentrated on luminescence properties from Yb3+ ions‐doped various hosts. Here, we report the observation of nonlinear negative transmittance (NNT) at continuous‐wavelength (CW) 980‐nm laser diodes (LDs) pumping in silicate oxyfluoride glass ceramics (GCs)‐containing CaF2:Yb3+ nanocrystals. The unique optical nonlinearity is analyzed based on energy‐level transitions, dynamic evolution, rate equation, and power transmission equation, which can be explained as the cooperative optical absorption for the intense CUCL of Yb3+ ions. The NNT in the CaF2:Yb3+ nanocrystals‐embedded GCs can be tailored with the power of a CW 980‐nm LDs, which possesses potential for the development of future optical limiters and switches.  相似文献   

3.
A new type of Ni2+-doped dual-phase glass ceramics (GCs) is developed by a simple one-step thermal-induced crystallization process. The GCs thus obtained are embedded simultaneously with hybrid ZnGa2O4 and ZnF2 nanocrystals (NCs). When pumped by a readily available 808 nm laser diode, an ultra-broad near-infrared (NIR) emission in a range of 1100−2100 nm is observed at room temperature. The NIR emission band with a full-width-at-half-maximum (FWHM) of more than 450 nm is comparable to the largest value ever reported in Ni2+-doped GCs, and much broader than those of single-phase GCs embedded with either pure ZnGa2O4 or ZnF2 NCs. The microscopic morphologies of the embedded hybrid NCs, and especially the distribution of Ni2+ in the dual-phase GCs are studied by analytical transmission electron microscopy (TEM). The intriguing photoluminescence properties of Ni2+ are thoroughly investigated by steady-state and time-resolved emission spectra. The GCs demonstrated herein hold promise as broadband solid-state NIR-light sources.  相似文献   

4.
The development of mid-infrared (MIR) broadband tunable lasers urgently needs high performance laser gain materials. Transition metal (TM) ions doped glass ceramics are considered to be efficient MIR broadband laser gain media. However, it is difficult to achieve gain because of the large scattering loss and low luminescence efficiency. In this paper, GeS2–Sb2S3–CsI–PbI2 chalcohalide glass ceramics containing CsPbI3 perovskite nanocrystals are fabricated by the melt-quenching method and subsequent heating treatment. The crystallization behavior of CsPbI3 nanophase and MIR luminescence properties of Ni2+ dopant are systematically investigated. Evidently, spherical CsPbI3 perovskite nanocrystals are precipitated and uniformly distributed in the glassy matrix, which can reduce the light scattering and make the chalcohalide glass ceramics have a high transparency. Moreover, an ultra-broadband MIR emission in the range of 2.5–5.5 μm is observed for the first time, to our best knowledge, from Ni2+-doped chalcohalide glass ceramics containing CsPbI3 perovskite nanocrystals. The newly developed Ni2+-doped chalcohaldie glass ceramics could be promising gain media for MIR broadband tunable lasers.  相似文献   

5.
In this paper, we report upconversion (UC) luminescence enhancement in LaBGeO5:Yb3+, Er3+ glass‐ceramics (GCs), surface crystallized glass‐ceramics (SCGCs) and ceramics compared with the as‐melt glass fabricated by the conventional melt‐quenching technique. Based on structural investigations, we find that the nucleation and crystallization of trigonal stillwellite LaBGeO5:Yb3+, Er3+ nanocrystals occur first at the glass surface before the following volume crystallization. The local site symmetry around rare earth (RE) ions which was evaluated using the Eu3+ ions as a probe together with Judd‐Ofelt theory calculations exhibits a clear increase with the devitrification of the glass. Consequently, complete crystallization of the glass leads to largest enhancement in the UC emissions of the LaBGeO5:Yb3+, Er3+ ceramics. We ascribe the enhancement of UC luminescence in the LaBGeO5:Yb3+, Er3+ GCs, SCGCs, and ceramics to the structural ordering and the improvement of site symmetry surrounding RE ions that minimizes the rate of nonradiative relaxation process.  相似文献   

6.
Dense (~98.5%), lithium aluminum silicate glass‐ceramics were obtained via the sinter‐crystallization of glass particle compacts at relatively low temperatures, that is, 790–875°C. The effect of P2O5 on the glass‐ceramics' sinter‐crystallization behavior was evaluated. We found that P2O5 does not modify the surface crystallization mechanism but instead delays the crystallization kinetics, which facilitates viscous flow sintering. Our glass‐ceramics had virgilite (LixAlxSi3‐xO6; 0.5 < x < 1), a crystal size <1 μm, and a linear thermal expansion coefficient of 2.1 × 10?6°C?1 in the temperature range 40–500°C. The overall heat treatment to obtain these GCs was quite short, at ~25 min.  相似文献   

7.
Tunable and ultrabroadband mid-infrared (MIR) emissions in the range of 2.5–4.5 μm are firstly reported from Co2+-doped nano-chalcogenide (ChG) glass composites. The composites embedded with a variety of binary (ZnS, CdS, ZnSe) and ternary (ZnCdS, ZnSSe) ChG nanocrystals (NCs) can be readily obtained by a simple one-step thermal annealing method. They are highly transparent in the near- and mid-infrared wavelength region. Low-cost and commercially available Er3+-doped fiber lasers can be used as the excitation source. By crystal-field engineering of the embedded NCs through cation- or anion-substitution, the emission properties of Co2+ including its emission peak wavelength and bandwidth can be tailored in a broad spectral range. The phenomena can be accounted for by crystal-field theory. Such nano-ChG composites, perfectly filling the 3–4 μm spectral gap between the oscillations of Cr2+ and Fe2+ doped IIVI ChG crystals, may find important MIR photonic applications (e.g., gas sensing), or can be used directly as an efficient pump source for Fe2+: IIVI crystals which are suffering from lack of pump sources.  相似文献   

8.
It is well recognized that a widely wavelength‐tunable mid‐infrared (MIR) fiber laser plays an important role in the development of compact and efficient coherent sources in the MIR range. Herein, the optimizing Er/Ho ratio for enhancement of broadband tunable MIR emission covering 2.6‐2.95 μm in the Er3+/Ho3+‐codoped transparent borosilicate glass‐ceramic (GC) fibers containing NaYF4 nanocrystals under 980 nm excitation was investigated. Specifically, the obtained GC fibers with controllable crystallization and well fsd‐maintained structures were prepared by the novel melt‐in‐tube approach. Owing to the effective energy transfer between Er3+ and Ho3+ after crystallization, the 2.7 μm MIR emission was obviously enhanced and the emission region showed a notable extension from 2.6‐2.82 μm to 2.6‐2.95 μm after the addition of Ho3+. Importantly, we conducted a theoretical simulation and calculation related to the MIR laser performance, signifying that the GC fiber may be a promising candidate for MIR fiber laser. Furthermore, the melt‐in‐tube approach will provide a versatile strategy for the preparation of diverse optical functional GC fibers.  相似文献   

9.
Optical gas sensors present fundamental and industrial importance considering their broad applications. Challenges remain to obtain new photonic materials with broadband emission covering the absorption spectrum of typical combustion gases. Here, broadband near‐infrared (NIR) photoluminescence (PL) spanning the wide absorption spectrum of typical combustion products is realized through instant precipitation of stable cubic perovskite KMgF3:Ni2+ nanocrystals inside an aluminosilicate glass matrix after melt‐quenching. Excited by an 808 nm laser diode, NIR luminescence with a peak centered at ~1624 nm and a bandwidth (FWHM) greater than 315 nm is observed, originating from 3T2g(3F) → 3A2g(3F) electronic transition of octahedral coordinated Ni2+ in KMgF3 GC. Controlled precipitation of these perovskite crystals from a supercooled aluminosilicate melt enables immediate encapsulation and, hence, stabilization in an inorganic glass phase. While the precipitation temperature has only a small effect on crystallite size, it controls the redox state of the melt and the degree of dopant incorporation into the crystalline phase so that PL performance can be optimized. Spontaneous crystallization of perovskite nanocrystals inside glass may offer a new way to stabilize these novel nanocrystals. Moreover, spontaneous crystallization can be attractive in the control of activator partitioning and in the fabrication of composite fiber devices with high transparency and emission gain. In the present case, this offers a potential platform for broadly tunable gain media, for example, for combustion gas sensing.  相似文献   

10.
This work reports on process‐induced impurities in rare‐earth ion: Dy3+‐doped selenide chalcogenide glasses, which are significant materials for active photonic devices in the mid‐infrared region. In particular, the effect of contamination from the silica glass ampoule containment used in chalcogenide glass synthesis is studied. Heat‐treating Dy‐foil‐only, and DyCl3‐only, separately, within evacuated silica glass ampoules gives direct evidence of silica ampoule corrosion by the rare‐earth additives. The presence of [Ga2Se3] associated with [Dy] on the silica glass ampoule that has been contact with the chalcogenide glass during glass melting, is reported for the first time. Studies of 0–3000 ppmw Dy3+‐doped Ge16.5As9Ga10Se64.5 glasses show that Dy‐foil is better than DyCl3 as the Dy3+ additive in Ge‐As‐Ga‐Se glass in aspects of avoiding bulk crystallization, improving glass surface quality and lowering optical loss. However, some limited Dy/Si/O related contamination is observed on the surfaces of Dy‐foil‐doped chalcogenide glasses, as found for DyCl3‐doped chalcogenide glasses, reported in our previous work. The surface contamination indicates the production of Dy2O3 and/or [≡Si‐O‐Dy=]‐containing particles during chalcogenide glass melting, which are potential light‐scattering centers in chalcogenide bulk glass and heterogeneous nucleation agents for α‐Ga2Se3 crystals.  相似文献   

11.
In this study, a new chalcohalide glass system, Ga2S3‐Sb2S3‐CsI, is reported. It has a glass‐forming domain composed of ~0‐35 mol% Ga2S3, ~15‐95 mol% Sb2S3, and ~0‐55 mol% CsI. The glasses have a wide transparent window of ~0.7‐13.5 μm, high third‐order nonlinear refractive indices of ~1.7‐8.7×10?14 cm2/W @ 1.55 μm, and relatively short zero group‐velocity‐dispersion wavelengths of 3.8‐5.15 μm. The glasses can dissolve more than 2 mol% active ions (e.g., Dy3+), and the doped glasses show intense emissions in the mid‐infrared. These superior properties demonstrate their good potentials for mid‐infrared applications such as thermal imaging, nonlinear photonics and lasers.  相似文献   

12.
Chalcogenide glasses show a unique potential for creating gradient refractive index (GRIN) lenses, which would reduce the size and weight of infrared thermal imaging system and remain/improve its performance. Here, we propose a new method that forms a GRIN chalcogenide glass–ceramics (GCs) by creating low refractive index (n) CsCl nanocrystals within a high n GeS2–Sb2S3 glass matrix. After specific gradient thermal treatment, the GRIN structure of Δ∼ 0.04 was formed through the gradient precipitation of CsCl. This work would pave a new path to design the GRIN chalcogenide GCs through a selective crystallization of halide crystals with low n.  相似文献   

13.
Through a careful composition design, new oxyfluoride glass‐ceramics (GCs) containing BaLiF3 nanocrystals with sizes of around 30 nm were prepared. Microstructural characterizations show interpenetrating phase separation in the sample with a composition of 15BaF2–15ZnF2–70SiO2, after thermal treatment at 580°C for 40 h which leads to the nanocrystallization of BaLiF3. The BaLiF3 nanocrystals embedded in the glassy matrix could provide Ba or Li sites for the incorporation of optically active rare earth and transition‐metal ions, which provides a possibility to explore novel photonic properties by the codoping of rare earth and transition‐metal ions in GC materials.  相似文献   

14.
Effect of As to Sb substitution on glass‐forming ability of As2Se3 glass under Ga additions was comprehensively studied using optical spectroscopy in visible and IR regions, differential scanning calorimetry, X‐ray diffraction as well as Raman scattering techniques. The crystallization processes enhanced by Ga additions to As2Se3 glass were significantly suppressed under such As to Sb substitution. Following conventional synthesis, it was possible to substitute up to 50% of As by Sb within Gay(As0.40?xSbxSe0.60)100?y cut‐section without essential impact on glassy state, thus improving optical properties in the IR region by lowering the phonon energy. In the case of Gay(As0.28Sb0.12Se0.60)100?y cut‐section, up to 8 at.% of Ga can be introduced without crystallization, whereas in case of Gay(As0.40Se0.60)100?y system, glass‐forming ability is limited just up to 3 at.% of Ga. The prepared Ga5(As0.28Sb0.12Se0.60)95 glass composition was shown to be the richest in Ga keeping its vitreous state, good optical and thermodynamic properties allowing further rare‐earth doping and fiber drawing.  相似文献   

15.
Er3+ ions‐doped germano‐gallate oxyfluoride glass‐ceramic containing BaF2 nanocrystals was prepared through conventional melt quenching and subsequent thermal treatment method. X‐ray diffraction patterns and transmission electron microscope images confirmed the formation of BaF2 nanocrystals in glass‐ceramics. Preferential incorporation of Er3+ ions into the BaF2 nanocrystals were confirmed by the absorption spectra and emission spectra, and enhanced upconversion emission and infrared emission were observed. Relatively high transmittance in the mid‐infrared region indicated great potential of this germano‐gallate oxyfluoride glass‐ceramics as host materials for the efficient mid‐infrared emission from rare‐earth ions.  相似文献   

16.
The photoluminescence properties of dopants are strongly correlated with their distributions in host phosphors, the knowledge of which, however, is not well established yet. In this paper, the distribution of the active dopants, for example, trivalent ytterbium (Yb3+) and bivalent nickel (Ni2+) in a highly transparent germanate glass-ceramic containing thermally grown Zn1+xGa2−2xGexO4 (0 ≤ x ≤ 1) nanospinels, is revealed by an analytical transmission electron microscope. The elemental mapping and linescan analysis confirm that both Yb3+ and Ni2+ accumulate preferentially in the germanium-substituted ZnGa2O4 nanospinels embedded in the glass. The influence of glass crystallization on the electric transition properties of Yb3+ is presented. An enhanced ultrabroadband near infrared emission of Ni2+ is observed as a result of efficient energy transfer from Yb3+ to Ni2+ accumulated in the nanocrystals. Discussions are given to account for the detailed mechanisms of the efficient energy transfer occurring between the dopants.  相似文献   

17.
We report Eu3+ doped transparent glass-ceramics (GCs) containing bismuth layer-structured ferroelectric (BLSF) CaBi2Ta2O9 (CBT) as the major crystal phase. The CBT crystal phase was generated in a silica rich glass matrix of SiO2-K2O-CaO-Bi2O3-Ta2O5 glass system synthesized by melt quenching technique followed by controlled crystallization through ceramming heat-treatment. Non-isothermal DSC study was conducted to analyze crystallization kinetics of the glass in order to understand the crystallization mechanism. The optimum heat-treatment protocol for ceramization of precursor glass that has been determined through crystallization kinetics analysis was employed to fabricate transparent GCs containing CBT nanocrystals, which was otherwise difficult. Structural analysis of the GCs was carried out using XRD, TEM, FESEM and Raman spectroscopy and results confirmed the existence of CBT nanocrystals. The transmittance and optical band gap energies of the GCs were found to be less when compared to the precursor glass. The refractive indices of the GCs were increased monotonically with increase in heat-treatment time, signaling densification of samples upon heat-treatment. The dielectric constants (εr) of the GCs were progressively increased with increase in heat-treatment duration indicating evolution of ferroelectric CBT crystals phase upon heat-treatment.  相似文献   

18.
Transparent oxyfluoride glass‐ceramics containing Er3+, Yb3+:Ca1?xLaxF2+x nanocrystals, which may have potential applications in the fields of solid‐state laser and luminescence, were prepared. Crystallization of Ca1?xLaxF2+x and behavior of Yb3+ and Er3+ during the heat treatment was investigated. Results showed that alumina content had a significant effect on crystallization of Ca1?xLaxF2+x in the SiO2–Al2O3–CaF2–LaF3 system. Due to the size of phase‐separated areas, the size of the crystals during the heat treatment did not change significantly. After crystallization of Ca1?xLaxF2+x in the glass, the majority of Er3+ ions incorporated into the Ca1?xLaxF2+x crystals during the heat‐treatment process. Time‐resolved luminescence of Er3+ ions in the samples around 842 nm showed that the solubility of Er3+ ions in Ca1?xLaxF3 crystals is higher than pure CaF2 crystals. The glass undergoes an enormous phase separation, which keeps the Yb3+ ions within the other separated phase. Therefore, only at high temperatures (790°C) or with a long heat‐treatment time (72 h), there is a possibility for Yb3+ ions to be incorporated into the fluorine phase.  相似文献   

19.
《Ceramics International》2023,49(20):32843-32849
Gradient index (GRIN) lens could promote the lightweight and miniaturization of optical imaging system, but the development of IR GRIN lens is still in its infancy. A new series of As–S–Se chalcogenide glasses (ChGs) possessing similar glass transition temperature, excellent thermal stability, and large refractive index variation was developed, and these properties enabled them to become a good glass material catalog for co-molding multilayered GRIN IR lens. By employing precision molding, layer-stacked GRIN ChG was co-molded with a maximum refractive index variation of 0.47 at 4 μm, which was correlated to the variation of Raman intensity and elemental content. A mid-IR optical imaging system was designed and fabricated using the GRIN ChGs, and IR images were obtained. This multilayered GRIN ChG could lead to 18% smaller and 35% lighter SWaP IR optical system.  相似文献   

20.
Novel transparent oxyfluoride glass‐ceramics containing KYb2F7:Ho3+ nanocrystals were successfully elaborated by melt‐quenching technique with further thermal treatment for the first time. Their structural and luminescent properties were investigated systemically by XRD, HRTEM, absorption spectra, upconversion spectra, and lifetime measurements. Under 980 nm laser excitation, all samples exhibited characteristic emissions of Ho3+. Attractively, the upconversion emissions of Ho3+, especially green and near‐infrared emissions, were enormously enhanced 190 times after crystallization. The incorporation of Ho3+ into KYb2F7 nanocrystals with lower phonon energy was responsible for this phenomenon. Our research may enrich the understanding of fluoride‐nanocrystals‐based transparent oxyfluoride glass‐ceramics.  相似文献   

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