Tellurite Glasses Research Articles

Incorporating Er:YAP Microcrystals Into Tellurite Fiber Using Volumetric Interface Doping

AbstractIn this semi‐quantitative study, laser crystal microparticles which are potentially capable of generating mid‐infrared (MIR) light are incorporated into MIR transmitting optical fibers using a volumetric interface doping technique that combines interface doping with volumetric doping. Using confocal microscopy with a refractive index matching fluid, the Er:YAP microcrystals (MCs) inside the tellurite glass fiber are observed based on the detection of the green upconversion fluorescence emission of Er3+ ions, produced under excitation at 976 nm and localized at the central region within the fiber. The key outcome from this proof‐of‐concept study is that MC particles that are fused with the glass during the fiber drawing process survived heat treatment because the MC particles are exposed for a short time to a glass fluid with high viscosity of ≈105 Pa.s, which prevented the glass from exerting a dissolution effect. The survival of the MCs demonstrated the viability of the doping technique for fabricating fibers with exotic crystal‐glass combinations for applications including good refractive index matching across the pump and lasing bands of rare earth ions. This latter parameter provides significant particle size flexibility whilst minimizing additional loss from scattering especially at MIR wavelengths where the MC diameter‐to‐wavelength ratio becomes smaller.

Tailoring the Structural and Optical Properties of Oxychloride Magnesium Tellurite Glass with the Addition of Samarium Ions

In this study, samarium-doped oxychloride magnesium tellurite glass with composition (79−x)TeO2−xMgO−20Li2O−1Sm2O3 (Series 1) and (79−x)TeO2xMgCl2−20Li2O−1Sm2O3 (Series 2) with 0 ≤ x ≤ 15 mol% was prepared by the melt-quenching technique. The structural and optical properties of synthesized samples were investigated, and the XRD results dictated an amorphous nature for both samples. The glass density of both Series 1 and 2 decreased with increasing MgO and MgCl2 content. However, the molar volume behaves in a completely opposite manner to an increase in MgO or MgCl2 content. FTIR spectra revealed from the vibrational wavenumber shift of TeO4 and TeO3 structural units showed a significant rise in HOH vibration mode, which implies its usefulness in boosting water and light absorption. Four absorbance bands were observed via UV-Vis NIR, while the indirect optical band gap around (3.42–3.36) eV and (3.42−3.30) eV for Series 1 and Series 2 were observed from UV-Vis spectroscopy. The emission spectra from the photoluminescence study revealed four distinct bands centered at 562.54, 599.14, 645.63 and 708.40 nm which are attributed to the transition from 4G5/2 – 6HJ/2 (J = 5,7,9,11) of states of Sm3+. The optimum glass with a composition of TeO-MgO 15% demonstrates a high potential for optical device development.

Chemical durability of optical temperature sensors made of tellurite glass: Effect of the alumina concentration

Tellurite glass is an amorphous material commonly doped with rare earth ions for the development of optical temperature sensors. Considering the intrinsic properties of glasses, it is expected that these sensors could be used in acidic environments and withstand temperature changes. However, this has not been fully demonstrated since most of the literature is limited to demonstrate the sensor operation under normal conditions. Additionally, there is a lack of information regarding the chemical durability of these glasses and methods to improve it. In this work, a special tellurite glass composition was proposed for the development of optical temperature sensor. The effect of the alumina concentration on the structure, chemical durability and emission properties of the glasses was evaluated. Chemical durability was assessed by monitoring the weight loss of glass samples after immersion in hydrochloric acid solutions at room temperature, vegetable oil or air at 150 °C. The results indicate that the addition of alumina increases the chemical durability of the glass and improves its emission properties. It was found that the average temperature estimated by the optical sensor had a relative error of 1.3 % due to the degradation of the glass caused by remaining immersed in a 1 N HCl solution for 60 days.

Enhanced upconversion luminescence of Er3+/Y3+ co-doped tellurite glasses for volumetric three-dimensional display

Large-sized Er3+/Y3+ co-doped tellurite glasses with high image quality were prepared by a conventional melt-quenching method for volumetric three-dimensional display. The effects of the concentration of Er3+ and Y3+ on the two-frequency upconversion luminescence properties and volumetric three-dimensional display were investigated. Under dual-wavelength excitation at 850 nm and 1550 nm, the two-frequency two-step upconversion luminescence intensity at 546 nm in the Er3+/Y3+ co-doped tellurite glass was significantly enhanced by about 44% compared with that in the Er3+ doped tellurite glass. However, the upconversion luminescence mechanism and its dynamic process were further obtained. A range of the high-resolution and high-contrast volumetric three-dimensional images can be achieved in the Er3+/Y3+ co-doped tellurite glass with optimal doping concentration, utilizing a coordinated control system of galvanometer scanner and digital micro-mirror devices. The results indicate that Er3+/Y3+ co-doped tellurite glass has promising potential for widely volumetric 3D displays.

High magnetic susceptibility-based vanadate tellurite glasses for magneto-optical device applications

Tellurite glasses modified with V2O5, Fe2O3, and Na2O (TVFN), along with Sm3+-doped Gd2O3 and Sb2O3 based tellurite (TVGSNSm) glasses evaluated for various properties. The thermal stability of these glasses, with a critical value of 105 °C advantageous to luminescence. Fourier transform infrared and micro-Raman bands were identified at 669, 745, 859, 943, and 1003 cm−1 in the deconvolution. Electron spin resonance revealed a signal at a magnetic field of 340.75 mT (g = 1.77). The magnetic hysteresis of TVFN glasses from a vibrating sample magnetometer which possess coercivity 62 mT and remanence 1.5х10−2 Am2/kg with a saturation magnetization 0.1975 A m2/kg and magnetic susceptibility as high as 0.1328. The magnetic nature confirmed by superconducting quantum interference device. Photoluminescence of Sm3+-doped TVGSNSm glasses excited by 408 nm showed 646 nm (red-orange) dominated emission band over the 603 nm band. These findings underscore the potential of TVFN glasses for applications in magneto-optical devices.

Titanium ion effects on the spectroscopic and electrical characteristics of germano silicate lead alumino tellurite glass ceramics for dielectric applications

The Glass-ceramics 10GeO2-(55-x) SiO2–29PbO–5Al2O3–1TeO2 doped with varying amounts of TiO2 (0 < x < 5 mol %) were prepared through the process of melt quenching followed by heat treatment. X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Differential Thermal Analysis (DTA) were used to analyze these glass ceramics besides the usual spectral studies like optical absorption, Electron Paramagnetic Resonance (EPR), Fourier Transform Infrared Spectroscopy (FTIR) and Raman. These investigations demonstrated the existence of crystalline phases that comprise complexes of Ti4+ as well as Ti3+ ions that were dispersed randomly. Additionally, it is seen that Ti3+ ions, which are more prevalent as TiO2 concentration rises, take up the tetragonally deformed octahedral positions inside the network of glass ceramics. FTIR spectra of the synthesized samples provided information regarding the existence of different structural units in the glass ceramic matrix, which included SiO4, GeO4, GeO6, PbO4, PbO6, AlO6, TeO4, TeO3, TiO4, and TiO6. At 30 °C, the 3 mol % Ti-doped sample has a minimum conductivity of 1.623 × 10−9 S cm−1. Therefore, the dielectric and spectroscopic investigations suggest that glass ceramics containing 3 mol% of TiO2 are rigid and appropriate for dielectric applications.

Gradient refractive index tellurite glass-ceramics for miniaturized and lightweight MWIR imaging

Tellurite glasses are highly anticipated for creating gradient refractive index (GRIN) lenses, which have the potential to be applied in the lightweight and miniaturization of optical imaging systems to improve their performance. However, it is still challenging to precipitate pure crystalline phases in tellurite glasses after heat treatment to control the refractive index via spatial variation of nanocrystal distribution. Here, we present a novel method for fabricating axial telluride GRIN glass via a gradient heat-treatment technique. Through the selection of glass composition and control of the heat treatment process, pure phase Bi4TeO8 nanocrystals with a high refractive index (n) can be precipitated in telluride glass with a lower refractive index. This allows the axial telluride GRIN structure of maximum refractive index difference Δn ∼ 0.1 to be obtained by modulating the spatial distribution and concentration of Bi4TeO8 nanocrystals. This work not only demonstrates the feasibility of producing GRIN lenses from tellurite glass but also lays the foundation for the future development of medium wave infrared (MWIR) imaging.

Temperature responsive behaviour of SrAl2O4(Eu, Dy):ZnGa2O4(Cr) phosphor-glass composite

The current investigation reports on laser spectroscopy and temperature-sensitive optical response of composite consisting of phosphors (ZnGa2O4:Cr3+ and SrAl2O4:Eu2+, Dy3+) coated on a tellurite glass layer. Based on this composite, a temperature sensor ranging from 298 K to 423 K demonstrates a remarkable temperature sensitivity. Various analytical techniques, such as X-ray Diffraction, Scanning Electron Microscopy, High-Resolution Transmission Electron Microscopy, laser spectroscopy, etc., were employed to analyze the prepared composite. The investigation reveals the presence of ZGO and SrAl phosphors with crystalline sizes of approximately 36 nm and 25 nm, respectively, while the particle size ranges from 400 nm to 600 nm. A dip coating method was utilized to deposit tellurite-phosphor layers on the glass substrate to create a temperature sensor. SEM analysis indicates a layer thickness of around 93 µm. The existence of Eu2+ and Cr3+ ions was confirmed through photoexcitation and emission spectra on a 405 nm laser excitation. The temperature-dependent luminescence was studied using a ratiometric technique, showing a linear variation with temperature, resulting in an excellent temperature sensitivity of about 1.41% K−1 at 298 K. Our preliminary study of the phosphor-tellurite composite suggests significant potential for extensive use in the field of dual-mode highly sensitive optical thermometry.

Stokes and anti-Stokes emission characteristics of Er3+/Yb3+ co-doped zinc tellurite glasses under 377 and 1550 nm excitations for solar energy conversion application

One of the best rare earth combinations for down- and up-converting the solar photons is Er3+/Yb3+. Therefore, at present, by using the traditional melt quench technique, zinc tellurite glasses doped with Er3+ and Er3+/Yb3+ were characterised. Several methods of down-conversion that result in the emission of 1000 nm from the acceptor (Yb3+) under excitation of donor (Er3+) were studied. On the other hand, the impact of acceptor (Yb3+) concentration and excitation pump power on the excited state absorption and its influence on the up-conversion emission (1000 nm) properties were investigated in detail under 1535 nm excitation. The studies on emission and decay results are discovered to be very significant. Suggesting that these glasses when used as conversion layers, can append the conversion efficiency of Si-based solar cells.

Experimental insights into increasing laser output at 2.8 µm in Er3+-doped zinc-tellurite fibers.

In this paper, we provide a new experimental insight into the lasing process in the erbium-doped tellurite glass fiber at high diode-pump powers and pumping pulse durations. It is shown that lasing occurs at two wavelengths. Initially, at a fixed wavelength of 2.718 µm corresponding to the luminescence maximum, lasing takes place during the first ∼100 µs from the start of the pump pulse, while the main laser power occurs at the 2.8 µm for the rest of the pump pulse and shifts to longer wavelengths with increasing pump power. At pumping durations essentially exceeding the lifetime of the upper laser level, no self-termination of lasing occurs; on the contrary, the lasing power increases, which indicates the key role of the energy transfer upconversion (ETU) process. We demonstrate for the first time to our knowledge efficient lasing with an average power of 60 mW and a pulsed energy of 1.2 mJ in an erbium-doped zinc-tellurite fiber.

High-efficiency 1.6 μm-band fiber laser based on single Er3+-doped tungsten tellurite glass with high mechanical strength through tailored glass network

In this study, the correlation between the Raman structure, thermal stability, and mechanical properties of TeO2-ZnO-La2O3–WO3 glasses with varying WO3 contents are systematically established. By exploring the critical point in the transformation process of glass network structural units, the optimal glass components of 74TeO2-12ZnO-5La2O3–9WO3 glass possess the maximum thermal stability (158 °C) and the highest mechanical properties at the same time. The maximum Vicker hardness and Young's modulus of the optimal glass can reach up to 4.007 GPa and 56.212 GPa, which are higher than those of the well-known TeO2-ZnO-Na2O (TZN) and TeO2-ZnO-La2O3 (TZL) glasses. Furthermore, the 0.5 mol% Er3+-doped glass at this critical point (TZLW-0.5Er) exhibits a higher laser figure of merit (54.29 × 10−21 cm2 ms), a larger laser gain bandwidth value (116 nm) and higher emission cross-sections at 1600 nm (2.52 × 10−21 cm2) and 1625 nm (1.06 × 10−21 cm2) than other host glasses. Finally, high-efficiency laser outputs at 1600 and 1625 nm based on TZLW-0.5Er glass fiber are successfully achieved by simulation. These results show the greater practical potential of TZLW-0.5Er glass with higher mechanical strength compared to TZN and TZL fibers for the 1.6 μm-band laser.

Atomic Structure Simulation and Properties’ Prediction using Machine Learning on Neodymium Oxide Nanoparticles Zinc Tellurite Glasses Aided by FTIR and TEM Analysis

The optical, structural, and physical characteristics of zinc tellurite glasses doped with neodymium oxide nanoparticles, which are produced by the melt-quenching method, were examined in this work. The amorphous character of the glasses was verified by XRD analysis. Using the Pair Distribution Function (PDF) and Monte Carlo simulations and visualisation for precise molecule distribution representation, an intuitive Python interface was created to emphasize these features. The density increased with increasing Nd2O3 concentrations, from 5346 to 5606 kg/cm2. Density data was used to infer the molar volume. The best projected density was achieved by the Gradient Boosting Regressor model, with a R2 of 0.9988 and an RMSE of 0.0032; the best predicted molar volume was achieved by linear regression, with a R2 of 1 and an RMSE of 2.67e-15. These models successfully represent the correlations between dopant concentration and glass properties, advancing our knowledge of the optical properties for further glass technology research.

Systematical investigations on the influence of Stark splitting of Er3+ on the potential wavelength-tunable of laser and optical amplification in several glasses

Er3+-doped glasses and fibers with broadband near infrared (NIR) emission have been widely applied in EDFA. Limited by optical gain band of Er3+-doped glasses and fibers, it was hardly meet to the demands of broadband amplification in the C + L band. In this work, six glass matrixes were employed for discussing the influence of glass matrix on the Stark splitting of Er3+ and the wavelength of laser output and amplification. The larger scalar crystal-field parameter NJ induce larger Stark splitting of Er3+-doped tellurite, germanate, and fluorophosphate glasses, which resulted in larger Δλeff. The Stark splitting of Er3+-doped tellurite, germanate, silicate, and phosphate glasses was mainly derived from homogeneous broadening, which be favor to obtain longer wavelength amplification and laser output. While that of Er3+-doped fluorophosphate and aluminate glasses was mainly derived from the inhomogeneous broadening, the amplification and laser output of Er3+ tend to operate in the shorter wavelength.

Exploring the impact of CuCl2 modification on structural variations and dielectric constant in bismuth borate tellurite glasses

Copper chloride doped boro-tellurite-based glass series with compositions 60TeO2-(25-x) Bi2O3–15B2O3-xCuCl2 (x = 0, 5, 10, 15, and 20) were synthesized using the traditional melt-quench procedure. The X-ray diffraction patterns of the examined glasses reveal their amorphous nature. The effect of CuCl2 addition on the glass network/structural units was studied using vibrational (FTIR/Raman) spectroscopy, and CuCl2 inclusion in the glass matrix resulted in a transformation from compact TeO4 to TeO3 structural units This shows that copper chloride acts as a modifier in the examined glass series, resulting in the creation of non-bridging oxygen (NBOs), meaning that the loosening of the glass network is further supported by a decrease in the glass transition temperature as CuCl2 content increases. UV–Vis DRS spectra of examined glasses reveal an absorption band corresponding to the typical transition of Cu2+ ions from 2B1g → 2B2g, situated in deformed octahedral sites in absorption spectra. As Cu+ concentration rises, the indirect optical band gap values drop from 2.94 eV to 1.75 eV. The metallization criterion values lie between 0.383 and 0.300 suggesting that these glasses are potential candidates for nonlinear optical applications. With an increase in Cu+ concentration, the values of molar refractive index (Rm) and molar electronic polarizability αm increases from 22.412 to 26.205 and 8.894 to 10.398 respectively, which correlate with increasing dielectric constant (ε′) values as the Cu+ amount increases. Further dielectric studies reveal non-Debye-type relaxation behaviour.

Simulation and calculation of the radiation attenuation parameters of newly developed bismuth boro-tellurite glass system

This paper presents a comprehensive simulation and calculation study of the radiation attenuation parameters for a newly developed bismuth boro tellurite glass system. Through advanced computational modeling and theoretical analysis, linear and mass attenuation coefficients (μ and μ/ρ), and other key radiation attenuation parameters of the studied glass system are thoroughly investigated across a range of photon energies. Utilizing state-of-the-art simulation techniques and theoretical models, the radiation shielding effectiveness of the glass system is evaluated, offering insights into its potential applications in radiation protection and shielding. We found that the ΣR values for fast neutrons are 0.10013, 0.10221, 0.10953, 0.11347 and 0.11383 cm−1 for BTBiBV-1, BTBiBV-2, BTBiBV-3, BTBiBV-4, and BTBiBV-5, respectively. The results of this study contribute to the understanding of the radiation attenuation properties of bismuth boro tellurite glasses and provide valuable information for their utilization in various fields, including medical imaging, nuclear power, and industrial radiography. Additionally, accurate modeling and characterization of attenuation parameters across different photon energies are crucial for designing effective radiation protection strategies and ensuring the safety of personnel and equipment in radiation environments.

Quantitative Analysis and Prediction of Elastic Properties of Tungstate–Tellurite Glasses Doped with Bi2O3

Quantitative Analysis and Prediction of Elastic Properties of Tungstate–Tellurite Glasses Doped with Bi2O3

Wide-Field Polarimetric Second-Harmonic Imaging for Rapid and Nondestructive Investigation of Laser-Induced Crystallization Phenomena.

The selective and controlled formation of nanocrystals in glass is emerging as a versatile method to achieve functional photonics, optoelectronics, and quantum devices, such as single-photon emitters. Here, we investigate the use of wide-field polarimetric second-harmonic (SH) microscopy as a method to rapidly and nondestructively examine nanoscale crystal arrangements in laser-processed glass. As a case study, we investigate tellurite glass, where the formation of a trigonal tellurium (t-Te) nanocrystalline phase after femtosecond laser exposure was recently demonstrated. Combined with theoretical models, we show that wide-field polarimetric SH microscopy offers comprehensive information on the nanocrystals' orientation, distribution, and chirality. With its high imaging throughput and spatial resolution, this method has the potential not only to significantly accelerate investigations on laser-induced glass crystallization processes but also to provide a valuable tool for in situ process monitoring.

The effect of rare earths (Nd3+, Er3+, Yb3+) additives on the radiation shielding properties of the tungsten oxide modified tellurite glasses

Abstract In this study, we have reported on the effect of the rare earth oxides on the radiation protection performance of the tellurite glasses. In order to determine the effect of rare earth oxides on the radiation shielding properties of tungsten oxide (WO3) modified tellurite glasses, three rare earth element oxides (Nd2O3, Yb2O3, and Er2O3) have been selected. The glass systems have been synthesized using the traditional melt quenching method and were doped with the different amount (1 %, 3 %, 5 %) of the oxides of rare earth elements (Nd2O3, Yb2O3, Er2O3). The linear attenuation coefficient, mass attenuation coefficient, half value layer, and effective atomic number of the synthesized samples were experimentally measured for 662, 1,173 and 1,332 keV gamma-ray energies which were emitted from 137Cs and 60Co radioactive sources. Measurements were conducted in narrow beam transmission geometry using a NaI(Tl) scintillation detector. In addition, all these parameters were calculated theoretically using the WinXCOM program in the energy region of 0.015–15 MeV. The addition of different types and amounts of rare earth oxides to the tellurite glass system was found to significantly enhance the radiation protection performance of the glasses. In particular, it was found that the radiation shielding characteristics of the glasses improved with increasing amount of rare earth doping, the TWYb5 glass system had the best radiation shielding properties, and there was a trend among the doped rare earth oxides in the form of Yb &gt; Er &gt; Nd according to their radiation shielding performance.

Er3+/Yb3+ Co-Doped Fluorotellurite Glass Fiber with Broadband Luminescence.

In order to address the 'capacity crisis' caused by the narrow bandwidth of the current C band and the demand for wide-spectrum sensing sources and tunable fiber lasers, a broadband luminescence covering the C + L bands using Er3+/Yb3+ co-doped fluorotellurite glass fiber is investigated in this paper. The optimal doping concentrations in the glass host were determined based on the intensity, lifetime, and full width at half maximum (FWHM) of the fluorescence centered at 1.5 µm, which were found to be 1.5 mol% Er2O3 and 3 mol% Yb2O3. We also systematically investigated this in terms of optical absorption spectra, absorption and emission cross-sections, gain coefficients, Judd-Ofelt parameters, and up-conversion fluorescence. The energy transfer (ET) mechanism between the high concentrations of Er3+ and Yb3+ was summarized. In addition, a step-indexed fiber was prepared based on these fluorotellurite glasses, and a wide bandwidth of ~112.5 nm (covering the C + L bands from 1505.1 to 1617.6 nm) at 3 dB for the amplified spontaneous emission (ASE) spectra has been observed at a fiber length of 0.57 m, which is the widest bandwidth among all the reports based on tellurite glass. Therefore, this kind of Er3+/Yb3+ co-doped fluorotellurite glass fiber has great potential for developing broadband C + L band amplifiers, ultra-wide fiber sources for sensing, and tunable fiber lasers.

∼2μm luminescence and energy transfer mechanism in highly Ho3+/Tm3+ co-doped bismuth glass

Highly Ho3+/Tm3+ co-doped Bi2O3-B2O3-Al2O3-BaF2 glasses were fabricated using the melt-quenching technique. The emission, radiation, and gain characteristics of the glass samples at the wavelength of 2.0 μm were examined analyzed. An intense and broad 2.0 µm emission, resulting from the 3F4→3H6 transition of Tm3+ and the 5I6→5I7 transition of Tm3+, was detected under the stimulation of 808 nm LD. The gain coefficient of Ho3+ in Ho3+/Tm3+ co-doped glass reaches 7.81 cm−1(at 2050 nm), which is 7.5 times as high as that of tellurite glass. Meanwhile, the large σemi × Δλeff(39.84 × 10-26 cm3) and σemi × τrad(16.10 × 10-21 cm2 ms) indicated BBTH4 glass possessed a large gain property and broadband. The energy transfer process of Tm3+: 3F4 ↔ Ho3+:5I7 was analyzed, the CD-A is 90 times larger than the CA-D. The Ho3+/Tm3+ co-doped Bi2O3-B2O3-Al2O3-BaF2 glasses show potential as broadband mid-infrared emission gain material.