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Abstract Transparent glass of x Eu 2 O 3 -(100- x)TeO 2 binary system is obtained by using the melt-quenching method and especially studied for x = 5 in x Eu 2 O 3 -(100- x)TeO 2 composition. Optical properties such as transmission, excitation, and emission spectra of Eu 2 O 3 -TeO 2 glass-ceramics are studied and carefully compared for the samples heated at different temperatures. The one step heat-treatment affects the crystallinities as well as phase formation and yields cubic [Eu 2 Te 6 O 15 ], orthorhombic [TeO 2 ], and tetragonal [TeO 2 ] phases depending on the heat treating temperature. Glass-ceramics of Eu3+-doped tetragonal [TeO 2 ] shows stronger emission intensity at wavelength of 613 nm with an excitation wavelength of 394 nm compared with that from cubic [Eu 2 Te 6 O 15 ] or Eu3+-doped orthorhombic [TeO 2 ]. Enhancement of emission intensity in Eu3+-doped tetragonal [TeO 2 ] is related to the local environment of Eu3+ ions substituted in tetragonal TeO 2 lattice. Highlights • Transparent 5Eu 2 O 3 -95TeO 2 binary glass is obtained by using the melt-quenching method • Phase formation cubic [Eu 2 Te 6 O 15 ], orthorhombic [TeO 2 ], and tetragonal [TeO 2 ] phases with temperature is observed • Stronger emission intensity at wavelength of 613 nm with an excitation wavelength of 394 nm was observed • Enhancement of emission intensity is related to the local environment of Eu3+ substituted in tetragonal TeO 2 lattice. [ABSTRACT FROM AUTHOR]

• The effect of heat-treatment on the structural, thermal and luminescence properties of Er3+/Ag NPs codoped tellurite glass was investigated. • A detailed study on the down-conversion emission in the Er3+ ions using an excitation wavelength of 488 nm was presented and discussed. • A high quantum efficiency exceeding 80% for the infrared emission at 1530 nm of Er3+ ions was obtained and compared to others glass systems. TeO 2 based glasses containing silver and doped by erbium ions were synthesized via the melting-quenching process. These glasses were subjected to an annealing treatment during different times above the glass temperature transition T g . Transmission electron microscope (TEM) and X-ray diffraction (XRD) revealed the growth of silver nanoparticles inside the tellurite glass host. Raman analysis was conducted to examine the structural characteristics of the glass systems and to detect any effects brought by the heat-treatment. Using 488 nm excitation, the down-conversion luminescence properties of erbium ions were studied and the processes implicated in the near-infrared emission (NIR) at 1530 nm were analysed. It was found that the heat-treatment enhanced the Raman signal and the downconversion emission of Er3+ ions. Especially, annealing for long time (at 440°C) resulted in an improvement of NIR emission intensity to the detriment of green emissions, as well as a considerable enhancement in the quantum yield and measured lifetime of the 1530 nm emission. The results indicate that the proposed glasses could be appropriate down-converting materials for improving the spectral response of some photovoltaic (PV) cells having bandgaps in the range 0.7–0.9eV. [ABSTRACT FROM AUTHOR]

Glasses with the chemical composition of (50-x-y) TeO 2 -30ZnO-10YF 3 -10NaF-0.5Tm 2 O 3 -yYb 2 O 3 (y = 0.5, 1.0, and 3.0 mol%) are developed using a melt-quenching method. Measurements of absorption, excitation, down and up-conversion emission spectra, and decay times were used to investigate the energy transfer processes. Cross-relaxation mechanisms caused the emission intensity to decrease at higher Tm3+ ion concentrations. The Tm3+/Yb3+ co-doped glasses showed strong up-conversion emission under the diode laser excitation at 978 nm. Studies on the dependence of pump energy revealed the mechanism underlying the up-conversion luminescence. According to the findings, the developed Tm3+/Yb3+co-doped glasses are also found to be a promising option for spectral conversion and emission (visible and near infrared) applications. [ABSTRACT FROM AUTHOR]

Raman spectroscopy has been used to elucidate the structure of tellurium (IV) oxide and its binary mixtures with thallium oxide both in the glassy state and in aqueous hydrochloric acid solutions. The addition of Tl 2 O in pure TeO 2 glass results in the progressive transformation of T e O 4 trigonal bipyramid (tbp) to T e O 3 trigonal pyramid (tp) units in agreement with the literature findings. Thallium oxide acting as a modifier for the tellurite network, reduces the functionality of the initial unit and lowers the continuous network rigidity. The spectral changes upon dissolution of the 0.2Tl 2 O-0.8TeO 2 glass in aqueous hydrochloric acid solution have also been measured revealing that the main structural units of the glass structure did not survive in a solution state and the connectivity of the glass network has completely collapsed. The systematics and the concentration dependence of the spectra acquired from different solutions indicate the presence of several chlorotellurate(IV) and hydroxochlorotellurate(IV) ionic species. The spectroscopic data are interpreted in such a way in order to indicate a dynamic equilibrium between the T e C l 6 2 − anion and the T e C l 4 (O H) − species. A combined analysis of the polarized and depolarized scattered intensity is presented here which aimed at elucidating the presence of additional species including the T e C l 4 (O H) 2 2 − and T e C l 3 (O H) species, respectively. The proposed model is discussed in the framework of the current phenomenological status of the field. • T l 2 O in pure T e O 2 glass results in T e O 4 to T e O 3 transformation. • Tl2O modifier lowers the continuous network rigidity by reducing functionality of T e O 4 unit. • Several chlorotellurate(IV) and hydroxochlorotellurate(IV) ionic species are detected in solutions. • A dynamic equilibrium between T e C l 6 2 − and TeCl 4 (OH) − species is established. • TeCl 4 (OH) 2 2 − and T e C l 3 (O H) species are also present in solutions. [ABSTRACT FROM AUTHOR]

In present study, the behavior of ytterbium (III) oxide, samarium (III) oxide and neodymium (III) oxide reinforced novel TeO 2 –B 2 O 3 –V 2 O 5 (TBV groups, tellurite-vanadium–boro) glasses groups are investigated against heavy charged particles, on mass stopping power, projected range and KERMA parameters. SRIM and PAGEX codes are used for determination of the mass stopping power, projected range and KERMA parameters in a kinetic energy range of 0–10 MeV. The highest KERMA values of TBV(X) glasses were achieved at 0.6 MeV. Among TBV(X) glasses, the TBVY1.5 sample with the highest material density (i.e. 5.01038 g/cm3) had the highest KERMA value. The TBVY1.5 sample has the lowest projected range values for alpha and protons with the same kinetic energy. The lowest values of mass stopping power were reported for the TBVY and TBVS groups, which had the highest density values among the analyzed glass samples. The TBVY1.5 sample provides the greatest stopping and slowing characteristics for alpha and proton kinetic energies ranging from 0 to 10 MeV. In this case, it can be said that these two glass groups may slow down alpha particles with a certain kinetic energy the most effectively. It can be concluded that TBV(Y) and TBV(S) glass groups might be useful for stopping the alpha, proton and electron particles. • Stopping parameters against heavy-charged particles are investigated. • Behaviours of tellurite glasses as a function of additive type are analyzed. • PAGEX and SRIM code are utilized for KERMA, MSP, and PR calculations. • TBV(Y)1.5 sample is observed with superior properties. • TBV(Y) and TBV(S) glass groups are highlighted with promising properties. [ABSTRACT FROM AUTHOR]

Spectroscopic properties of Eu3+-doped tellurite glass composed of 74 TeO 2 + 15 ZnO +5 Nb 2 O 5 + 5 TiO 2 + 1.0 Eu 2 O 3 (mol %) have been investigated. Phonon energy of the host glass constituents that are linked up with the Eu3+ ions have been evaluated from the photoluminescence excitation spectrum which is found to be 760 cm−1. By utilizing the emission spectrum, the Judd-Ofelt (JO) intensity parameters (Ω λ , λ = 2 and 4) are calculated. The obtained JO parameters are utilized for evaluating the emission cross-sections (σ(λ p)) of 5D 0 → 7F J (J = 1, 2 and 4) transitions. An intense emission at 613 nm due to the transition5D 0 → 7F 2 is observed upon 465 nm excitation. Among these, the 5D 0 → 7F 2 (613 nm) transition has been exhibited the highest (σ(λ p)) value and it found to be 2.11 × 10−22 cm2. For the 5D 0 level, quantum efficiency (η) is corroborated theoretically as 58.4% and it is in line with absolute quantum yield of 56.7% obtained by Integrating sphere method. The results of Eu3+-doped TZNTEu1.0 glass are significant for the development of solid-state lighting devices at around 613 nm under the excitation of 465 nm. • Phonon energy was evaluated with help of excitation spectrum and found to be 760 cm-1. • Quantum yield of 56.7 % has also been obtained by Integrating sphere method. • The emission cross-section has been evaluated as 2.13 x 10-22 cm2 and lifetime is 793 μs. • TZNTEu glass is significant for the development of solid-state lighting at around 613 nm. [ABSTRACT FROM AUTHOR]

Two series of tellurite glasses with molar compositions of (55TeO _2 –2Bi _2 O _3 –(41-x) ZnO–2Na _2 O–xNd _2 O _3 (x = 0.5, 1.0, 1.5, 2.0 and 2.5) and 55TeO _2 –2Bi _2 O _3 –(41-x) ZnO- x Na _2 O-2Nd _2 O _3 (x = 1.0, 2.0, 3.0, 4.0, 5.0) were fabricated using melt quenching technique. Based on the measured densities, refractive indices and absorption spectra, physical and spectroscopic properties of these two-glass series are evaluated and compared. Whereas substitution of ZnO by Nd _2 O _3 causes the values of density and refractive index increase, the substitution of ZnO by Na _2 O has been shown to impact the glass density and refractive index in the opposite manner. Molar volume of both series increases with an increase of either Nd _2 O _3 or Na _2 O concentrations. In this regard, a dynamical model explaining the density and molar volume was proposed. Additionally, Judd-Ofelt theory was applied in order to predict the physical and laser properties of the two glasses series as a function of glass compositions, i.e., Judd-Ofelt parameters Ω _t ( t = 2, 4, 6), branching ratios ( β ), calculated lifetimes ( τ ), the emission to exited state absorption intensity ratio ( A _em / A _ESA ) and spectroscopic quality χ = Ω _4 /Ω _6 . Equations to relate χ with branching ratios for laser transitions ^4 F _3/2 to ^4 I _J’ (with J ′ = 9/2, 11/2, 13/2 and 15/2) were also derived.

This work discusses some new insights into the structural and thermal properties of the glass system TeO2-Li2O-MoO3. Glasses in the composition (80-2x)TeO2 − xLi2O − (20+x)MoO3 (TLM) where x=0,5,10,15 and 20 mol% were prepared by the melt-quenching technique and were characterized by X-ray diffraction (XRD), Raman spectroscopy, density, refractive index, and differential scanning calorimetry (DSC). XRD data confirmed the amorphous character of the samples. In addition, the glass transition (Tg), the onset crystallization (Tx), and the first exothermic peak at the crystallization temperatures (Tc) were determined from DSC scans. Thermal stability (ΔT=Tx-Tg) increases up to x=15mol% followed by a decrease for higher x. Raman results showed that when x increases, the Te-O-Mo linkages form, meaning that Li2O addition breaks the Te units and Mo-units in the studied glasses. The Te-O-Mo linkages enhance the thermal stability values, increasing the oxygen packing density. The formation of these linkages also alters the refractive index and the electronic polarizability behaviors. In summary, this work shows that the addition of Li2O in the TeO2-MoO3 system enhances the thermal stability and changes the electronic polarizability behavior, showing the potential of the studied material for technological applications. [ABSTRACT FROM AUTHOR]

Abstract In the present study, crystallization behavior of tungsten molybdenum tellurite glasses was investigated by non-isothermal methods using differential scanning calorimetry (DSC), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) techniques. Thermal properties of glasses were investigated to calculate the values of glass transition temperature (T g), crystallization temperature (T c / T p), temperature difference (Δ T), thermal stability (S), glass transition activation energy (E g) and fragility parameter (m). Average cross-link density (n c ¯) values were calculated for the physical investigation of the glasses. The crystallization kinetics was studied at different heating rates and the values of Avrami constant (n) and morphology index (m) were calculated from the Ozawa equation and the activation energy of crystallization (E c) was determined using the modified Kissinger equation. The crystallized and/or transformed phases and their morphologies were determined by XRD and SEM analysis. Studied glass compositions were found to be thermally stable, resistant to crystallization and therefore suitable for opto-electronic applications. Highlights • Glasses in the WO 3 -MoO 3 -TeO 2 system were synthesized. • Fragility character of the glasses is found to be between strong and fragile. • The surface crystallization of α-TeO 2 and WO 3 phases were observed. • 3D growth of α-TeO 2 and WO 3 crystals and crystallization of MoO 3 phase were observed. [ABSTRACT FROM AUTHOR]

Abstract Quinary tellurite glass system in the percentages of 75TeO 2 –5Li 2 O–10ZnO–(10–x) Nb 2 O 5 –xEr 2 O 3 where (x = 0.0, 0.5, 1.0, 1.5, 2.0, and 2.8 mol%) have been prepared and characterized. Both Fourier-transform-infrared (FTIR) and Raman spectroscopies were performed to study the structural changes correlated with the glass network. The thermal characteristics of the system were specified which showed a higher thermal stability (>100 °C) due to the formation of more bridging oxygen's (BO's) revealed by (FTIR) and Raman spectroscopies. The optical absorption spectra within near UV–visible regions were performed, and exhibited nine absorption bands centered around 1536, 977, 798, 653, 545, 524, 490, 450, and 443 nm corresponding to the 4I 15/2 ground state to the various excited states 4I 13/2 , 4I 11/2 , 4I 9/2 , 4F 9/2 , 4S 3/2 , 2H 11/2 , 4F 7/2 ,4F 5/2, and 4F 3/2 respectively. The same measurement also showed increasing values of the optical band gap (E g) form 2.70 to 2.90 (eV) and decreasing the refractive index (n) from 2.48 to 2.42. Both the extinction coefficient data and the complex dielectric functions of the glasses were estimated. The different optical parameters were distinctly affected by increasing the Er 2 O 3 (mol %) and the structural changes. The radiative properties of the glass were calculated using J-O parameters. The Branching ratio (β) of 4I 13/2 → 4I 15/2 transition peaked at 1520.48 nm for Er3+ ions has the highest value (1.000) also, the radiative lifetime (τ) of the same transition changed from 1.4510 to 1.8483. The gain cross-section of the laser transition level from 4G 11/2 → 4I 15/2 changed from 1.44 × 10−20 to 1.92 × 10−20 cm−1 in the existing glass system. The acquired results exhibited that the existent glass can be a good candidate in the fiber drawing and laser, non-linear optical applications. Graphical abstract Unlabelled Image Highlights • TeO 2 –Li 2 O–ZnO–Nb 2 O 5 –Er 2 O 3 glasses with different Er 2 O 3 (mol%) have been prepared. • The thermal stability of the glass increased with increasing Er 2 O 3 (mol %). • The refractive index decreased with increasing Er 2 O 3 (mol %). • The glass became optically more dispersive with increasing Er 2 O 3 (mol %). • Judd-Ofelt parameters were calculated as a function of increasing Er 2 O 3 (mol %). [ABSTRACT FROM AUTHOR]

Glasses of the 17ZnO·32CdO·51TeO 2 system doped with Eu 2 O 3 (0–0.75 mol per 100 mol of oxides) were obtained. Non-isothermal differential scanning calorimetry (DSC) tests showed that the glass transition temperature varied in the range of 354° to 371 °C with the addition of Eu 2 O 3 . The samples were exposed to a thermal treatment in a laboratory oven at 420 °C. X-ray diffraction analysis of the treated samples showed crystalline phases of a variety of metallic oxides, the intensities of which decreased as the Eu doping amount in the samples increased. In all samples, the strongest peak corresponded to ZnTeO 3 with a crystallite size of about 36 nm. Fourier Transform Infrared Spectroscopy showed that CdO and ZnO change their role from modifier to a glass former. Raman spectra showed characteristic bands corresponding to γ–TeO 2 . The observations suggest that Eu 2 O 3 induced structural changes which in turn led to the formation of molecular oxygen in the interstitial network. Deconvolution analysis of Raman spectra and High-Resolution Transmission Electron Microscopy images confirmed the formation of Te 2 O 5 , ZnTeO 3 and Te nanocrystals. Photoluminescence analysis showed that Eu ions are incorporated as Eu 3+ and no reduction occurred after heat treatment. [ABSTRACT FROM AUTHOR]

In materials engineering design understanding and prediction over the physical properties are essential to develop new class of functionalized materials. The objective of this work is to assess the radiation shielding properties for Bi 2 O 3 - V 2 O 5 - TeO 2 glass system. For this aim, the MCNP5 Monte Carlo code was used to estimate the mass attenuation coefficients (μ/ρ) for the Bi 2 O 3 - V 2 O 5 - TeO 2 glasses in the energy range of 0.356-1.33 MeV. The MCNP5 values of μ/ρwere verified by XCOM at the selected energy range.The results showed that BiVTe6 and BiVTe1 glass samples have the highest and lowest values of mass attenuation coefficient respectively. The addition of Bi 2 O 3 in the glass samples leads to a reduce in HVL and MFP values at all photon energies. Hence, BiVTe6 glass sample possesses the lowest HVL and MFP values, thus this glass sample has better shielding properties in comparison with the other samples in this work.The exploitation of their useful shielding properties may open many new technological applications in optoelectronics and radiation protection. [ABSTRACT FROM AUTHOR]

The aim of the present work is to verify the synthesis of zinc tellurite by crystallization of glasses in TeO2 - Bi2O3 - ZnO - Nb2O5 system. The investigation refers to TeO2 - based glasses containing up to 10 mol % of Nb2O5 and Bi2O3 and ZnO content raging from 5 mol % to 10 mol %. Several glasses are selected and heat treated for 6h at 500°C. The XRD analysis detects formation of several ZnTeO3, TeO2 and ZnO crystalline phases. Additional information for the formation of ZnTeO3 crystalline phase is obtained by infrared spectroscopy (IR). There is a difference in the IR spectra of the crystalline sample of 50TeO2.50ZnO (ZnTeO3) and those of the multicomponent glasses. The spectra analysis shows that the glass network consists mainly of TeO4 (tbp) units, while TeO3 (tp) are the main structural units in the crystalline ZnTeO3 phase. The microstructure of the selected crystallized samples is examined by SEM analysis. [ABSTRACT FROM AUTHOR]

The radiation shielding performance of tellurite tungsten glasses with different antimony oxide (Sb 2 O 3 ) content was studied using Monte Carlo simulation MCNPX and WinXCOM software. The mass attenuation coefficients were computed for photon energies of 0.662, 1.173, 1.274 and 1.332 MeV. Moreover, The transmission factor of the selected glasses was calculated at a different thickness from the incident and transmitted photons. It was found that the transmission factor of the investigated glasses lies within 0.11–0.28 range. Also, it was found that the MCNPX and WinXCOM results were matched with each other. It can also be concluded that the high density TSW5 glass sample has the maximum shielding effect over the other samples because of the high weight fraction of the highest atomic numbers (i.e. W, Z = 74) as well as its high density. [ABSTRACT FROM AUTHOR]

The mass attenuation coefficient, effective atomic number, and half value layer of (75-x) B 2 O 3 -xBi 2 O 3 -10Na 2 O-10CaO-5Al 2 O 3 glass system (x = 0, 5, 10, 15, 20 and 25mol%) with potential applications as radiation shielding materials, have been investigated in the energy ranging from 31 keV to 662 keV using the MCNPX Code. Appreciable variations are found for these parameters by changing the energy of a photon well as the chemical composition of the investigated glasses. The addition of Bi 2 O 3 to the present glasses leads to increase μ/ρ values which indicates that Bi has a strong effect on improving shielding ability of the present glass system. The numerical simulation mass attenuation coefficients are compared with theoretical data obtained from XCOM software. Satisfactory agreement reported indicates that the Monte Carlo code can be utilized to make further calculations on the radiation shielding characteristics of other glass systems, an ability especially helpful in cases where no analogous experimental results available. [ABSTRACT FROM AUTHOR]

Featured Application: Supercontinuum generation in novel infrared fibers from high-repetition-rate femtosecond mode-locked laser pulses provides mid-infrared radiation with very attractive features such as high coherence and spectral power density over an ultra-broad spectral range, thus opening new prospects for remote sensing applications, in particular through mid-infrared spectroscopy. Mid-infrared supercontinuum generation from 1.5 to 4.5 µm with sub-nanojoule femtosecond pump pulses is demonstrated by using a short segment of dispersion-engineered step-index tellurite fiber with very low OH content. Distinct group-velocity dispersion regimes in a simple design of step-index tellurite fiber are also reported, which allows to choose the nonlinear pulse propagation regime according to the required tailoring of the supercontinuum source. Numerical simulations based on the generalized nonlinear Schrödinger equation are used to determine optimized fiber parameters before experimental demonstrations. We also analyse the coherence properties of the resulting supercontinuum sources. [ABSTRACT FROM AUTHOR]

We investigate the thermal effects of Er 3+ doped tellurite glasses on the upconversion properties. It is found that the sensitivity of the thermometer based on the FIR technique increases monotonously with the decreasing doping concentration. However, low doping leads to weak upconversion intensity and further decrease the sensing accuracy, which makes it difficult to achieve the high sensitivity and accuracy simultaneously. Influences of the irradiating laser power on the sensing behaviors were studied in the purpose of enhancing the signal intensity. It is found that the heating effect of incident laser (up to hundreds of mW) can be neglected, indicating the feasibility of using high laser power and low doping sample to produce both high sensitivity and high accuracy. In addition, this paper respectively discusses the mechanisms of the upconversion processes and the concentration dependent sensitivity. [ABSTRACT FROM AUTHOR]

This work presents a spectroscopic investigation of tellurite glasses with the composition 65TeO 2 -15Li 2 O-20ZnO doped with different concentrations of Er 2 O 3 . Optical absorption and emission spectroscopy were performed at room temperature to determine emission properties of Er 3+ in the visible and near-infrared regions. The samples presented intense green emission due to the H 11 / 2 2 → I 15 / 2 4 and S 3 / 2 4 → I 15 / 2 4 transitions. Emission intensities at 992 and 1550 nm exhibit a relative increase with increasing doping concentration. Luminescence decay curves for the S 3 / 2 4 → I 15 / 2 4 transition follows a non-exponential behavior, while the I 11 / 2 4 → I 15 / 2 4 and I 13 / 2 4 → I 15 / 2 4 transitions presented simple exponential behavior with high lifetime values. Under 975 nm excitation, upconversion luminescences in the green and red regions are observed, with a relative increase for red emission as function of doping concentration. The possible mechanisms considering multi-phonon relaxation, energy transfer and cross-relaxation processes were discussed for green and red emissions under excitations at 488 and 975 nm. The square dependence of green emission on the excitation power indicates two photons contribution to the upconversion emission. The full width at half-maximum values of emission at 1550 nm increased with increasing Er 3+ concentration, showing the potential of the studied material as infrared amplifier. [ABSTRACT FROM AUTHOR]

The structure of WO 3 -TeO 2 glasses containing 15, 20 and 25 mol% WO 3 are studied by neutron diffraction (ND), high energy X-ray diffraction (XRD) and X-ray Absorption Near Edge spectroscopy (XANES). The short-range structural properties of glasses i.e. Te O and W O speciation, coordination number distributions, bond-lengths, and the O Te O, O W O and O O O bond angle distributions in the glass network are determined by the Reverse Monte Carlo (RMC) simulations of the ND and XRD data. RMC technique successfully determined all partial pair correlation functions and the coordination number distributions revealed that glass network consists predominantly of TeO 4 and WO 4 units with small amounts of triangular, penta and hexa co-ordinated units. The average W O and Te O bond lengths are in the ranges: 1.69–1.75 ± 0.01 Å and 1.99–2.00 ± 0.01 Å respectively. Both W O and Te O correlation peaks are asymmetrical, that indicate a distribution of their bond lengths in the respective structural units. The O-Te-O bond angle distribution has a peak at 107 ± 2°. Similarly the O-W-O bond angle distribution has a peak at 108 ± 5°. On increasing the WO 3 concentration from 15 to 25 mol%, the average Te O coordination number decreases from 3.80 to 3.61 ± 0.02 due to the structural transformation: TeO 4  → TeO 3 , similarly the W O coordination also decreases and is in the range: 3.79–3.67 ± 0.02. XANES studies found that the oxidation state of Te and W ions in the glasses are 4 + and 6 + respectively. [ABSTRACT FROM AUTHOR]

Nonlinear optical properties of multicomponent tellurite glasses doped with Er 3+ ions were investigated by open aperture Z-scan measurements. Compositional and linear optical properties of the glasses were examined by the energy dispersive X-ray spectrum and UV–vis–NIR absorption spectrum analysis respectively. The mechanism behind the optical nonlinearity and optical limiting efficiency was successfully explained by evaluating the physical properties such as density, refractive index and polarizability of the glasses. The nonlinear properties critically depend on the polarizability, which is found to increase with the addition of Er 3+ ions by the creation of non-bridging oxygen ions. By the systematic addition of Er 3+ ions, we have dictated the physical properties and thus tuned the optical limiting efficiency of the glasses. This makes the Er 3+ -doped multicomponent tellurite glasses flexible tunable optical limiters for potential device applications. [ABSTRACT FROM AUTHOR]

The excitation and emission obtained from an Er3+-doped tellurite glass with embedded silver nanoparticles (SNPs) through nanostructured surfaces consisting of a square lattice of nanoholes (squares or circles) in a silver thin film are addressed. The periodic nanostructures were fabricated with a focused gallium ion beam on a silver thin film deposited onto an Er3+-doped tellurite glass with embedded SNPs. The Er3+ microluminescence spectra were measured in the far field (510- to 590-nm wavelength range). The emission observed through the plasmonic nanoholes is caused by the excitation of the Er3+ ions via extraordinary optical transmission from the periodic nanostructures. Two coupling types are proposed: (i) one between the SNPs and the Er3+ ions (electric dipole type) and (ii) a resonant coupling between the SNPs (localized surface plasmon resonance) and a silver thin film (surface plasmon polariton). These two couplings modify the local field, which improves the emission intensity of Er3+. A dependence of the intensity emission with the geometrical shape of the nanoholes and the number of elements of the square lattice was observed. These findings can be very useful for nanophotonic device applications employing a transparent medium with optical gain. [ABSTRACT FROM AUTHOR]

The materials under investigation were the tellurite glasses. Basic glasses and glasses doped with erbium Er 3+ ions were examined. The positron lifetime measurement method PALS (Positron Annihilation Lifetime Spectroscopy) and the Raman spectroscopy were applied in order to analyse their structural properties. The proposed PALS method allows to identify structural defects in amorphous materials (glasses, ceramics and polymers) that are difficult to detect with the use of other traditional measuring methods. The conducted studies revealed two positron lifetime components τ 1 and τ 2 . On the basis of the two-state model, positron capture parameters were calculated, which allowed to draw conclusions concerning the nature and degree of defects of the examined tellurite glasses. Application of the Raman spectroscopy resulted in assessment of the effect of Er 3+ on the structure of the examined material. [ABSTRACT FROM AUTHOR]

This paper reports on the effect of varying concentration of erbium (Er3+) on the (70‐x/2) TeO2 − (20‐x/2) B2O3 −10 ZnO − x Er2O3 (where x = 0, 0.5, 1.0, 2.0, 2.5 mol.%) system, fabricated using the conventional melt quenching technique. The impact of Er3+ on the structural, physical, and optical properties of these zinc borotellurite glasses is investigated using Fourier transform infrared spectroscopy (FTIR), density measurements and UV–vis spectroscopy. The amorphous nature is confirmed using X‐Ray diffraction. FTIR results reveal that the glass is formed of fundamental borate and tellurite network units. The addition of Er2­O3 results in the formation of TeO3 at the expense of Te‐O‐Te linkage. The UV–vis spectroscopy results show that Er3+ enter the glass matrix showing absorption peaks corresponding to 4f‐4f transitions of trivalent Erbium ions (Er3+) from ground state 4I15/2 to the excited states 4F5/2, 4F7/2, 2H11/2, 4S3/2, 4F9/2, 4I9/2, 4I11/2, and 4I13/2. The optical band gap tends to decrease and refractive index increases with the increase in Er3+ concentration hence making these materials more efficient for the optical devices such as light emitting devices and image sensors. [ABSTRACT FROM AUTHOR]

This paper reports on the effect of varying concentration of erbium (Er3+) on the (70‐x/2) TeO2 − (20‐x/2) B2O3 −10 ZnO − x Er2O3 (where x = 0, 0.5, 1.0, 2.0, 2.5 mol.%) system, fabricated using the conventional melt quenching technique. The impact of Er3+ on the structural, physical, and optical properties of these zinc borotellurite glasses is investigated using Fourier transform infrared spectroscopy (FTIR), density measurements and UV–vis spectroscopy. The amorphous nature is confirmed using X‐Ray diffraction. FTIR results reveal that the glass is formed of fundamental borate and tellurite network units. The addition of Er2­O3 results in the formation of TeO3 at the expense of Te‐O‐Te linkage. The UV–vis spectroscopy results show that Er3+ enter the glass matrix showing absorption peaks corresponding to 4f‐4f transitions of trivalent Erbium ions (Er3+) from ground state 4I15/2 to the excited states 4F5/2, 4F7/2, 2H11/2, 4S3/2, 4F9/2, 4I9/2, 4I11/2, and 4I13/2. The optical band gap tends to decrease and refractive index increases with the increase in Er3+ concentration hence making these materials more efficient for the optical devices such as light emitting devices and image sensors. [ABSTRACT FROM AUTHOR]

Sm 3+ singly and Sm 3+ /Yb 3+ co-doped tellurite glasses have been prepared by melt quenching technique. The prepared glasses are characterized through optical absorption, excitation, fluorescence and decay rate measurements. Judd-Ofelt theory has been employed to find the radiative properties and also stimulated emission cross-sections by using Futchbauer-Ladenbergh formula. The energy transfer mechanism from Sm 3+ to Yb 3+ ion has been analyzed. The theoretical energy transfer efficiency and quantum efficiency values were calculated from the decay curves of the Sm 3+ /Yb 3+ co-doped tellurite glasses. The results indicate that the prepared glasses can be used as visible to near-infrared converting material to improve the conversion efficiency of silicon solar cells. [ABSTRACT FROM AUTHOR]

This article focuses on the shielding properties among 21 tellurite glass samples in the form of TeO 2 -A n O m , TeO 2 -WO 3 -B n O m and TeO 2 -WO 3 -Er 2 O 3 -PbO where A n O m = La 2 O 3 , CeO 2 , Sm 2 O 3 , MnO 2 , CoO 3 , Nb 2 O 5 ,B n O m = Er 2 O 3 , La 2 O 3 , Sm 2 O 3 and CeO 2 mol%. The mass attenuation coefficient, μ/ρ have been computed within the energy range 0.01 MeV‒20 MeV using WinXCom software. The obtained mass attenuation coefficients are then utilized to calculate effective atomic numbers, Z eff , half value layers, HVL and mean free path, MFP. In addition, the macroscopic effective removal cross-section for fast neutron (Σ R ) values was also evaluated. In addition, variation of the shielding parameters is compared with other tellurite, borate and silicate glasses to explore the superior shielding properties of tellurite glasses from gamma rays than other glasses. [ABSTRACT FROM AUTHOR]

The Dy 3+ and Eu 3+ single-doped and co-doped tellurite glasses containing silver nanoparticles (NPs) were prepared by the Ag + -Na + ion-exchange method. The influence of local surface plasmon absorption (LSPR) at the 455 nm of Ag NPs on the photoluminescence (PL) of Dy 3+ and Eu 3+ single-doped and co-doped tellurite glasses was investigated. The results indicated that the different PL enhancement factors of tellurite glasses single-doped with Eu 3+ and Dy 3+ were obtained by adjusting the overlapping relationship between excitation or emission wavelength and the LSPR of Ag NPs. When the excitation wavelength is overlapped with the LSPR of Ag NPs, the larger enhancement factor was obtained in the Eu 3+ doped tellurite glasses due to the excitation field enhancement. When the emission wavelength is overlapped with the LSPR of Ag NPs, the selective enhancement of 485 nm emission of Dy 3+ is obtained due to the radiative decays rate increasing besides the excitation field enhancement. The energy transfer enhancement from Dy 3+ to Eu 3+ caused by the LSPR of Ag NPs was observed in the Dy 3+ and Eu 3+ co-doped glasses. The Dy 3+ and Eu 3+ co-doped tellurite glasses exhibited the white light emission upon the blue chip excitation, which indicated that they have a potential application for the blue converted WLEDs. [ABSTRACT FROM AUTHOR]

A series of ternary glasses in the MeO–PbCl 2 –TeO 2 (MeO = Bi 2 O 3 , MoO 3 , Sb 2 O 3 , WO 3 , ZnO) system have been synthesized by conventional melt quenching technique. Thermal properties of glasses – glass transition ( T g ) and crystallization ( T c / T p ) temperatures, temperature difference (Δ T ) and thermal stability (S) values – were determined using differential scanning calorimetry. The influence of transition metal oxides on refractive index, position and shift rate of absorption edge, optical band gap energy ( E opt ) and Urbach energy (Δ E ) was investigated and their dependence on temperature was studied. The E opt and Δ E values of all glasses studied in this work were found to be comparable with the values corresponding to some semiconductors. The glasses under study show great potential for applications in optoelectronics. [ABSTRACT FROM AUTHOR]

Different concentrations of Tb 3+ -doped oxyfluoro tellurite (TWGTb) glasses were prepared by conventional melt quenching technique and characterized for green laser applications. The Judd-Ofelt theory was applied to evaluate various spectroscopic and radiative parameters. The TWGTb glasses exhibit 5 D 3 → 7 F 5-3 and 5 D 4 → 7 F 6-0 transitions when excited at 316 nm radiation. The variation of intensity of 5 D 4 → 7 F 5 (Green) and 5 D 3 → 7 F 4 (Blue) transitions and the green to blue (I G /I B ) intensity ratios were studied as a function of Tb 3+ ions concentration. The laser characteristic parameters such as effective bandwidth (Δλ eff ), stimulated emission cross-section (σ e ), gain bandwidth (σ e  × Δλ eff ) and optical gain (σ e  × τ R ) were determined using the three phenomenological Judd-Ofelt intensity parameters. The fluorescence decay profiles of 5 D 4 metastable level exhibit single-exponential nature for all the samples. Based on the experimental results we suggest that the 1.0 mol% of Tb 3+ -doped TWGTb glass could be a suitable laser host material to emit intense green luminescence at 545 nm. [ABSTRACT FROM AUTHOR]

The thermal characteristics of the quaternary TeO 2 –ZnO–Na 2 O–Er 2 O 3 glass system as a function of rising Er 2 O 3 mol% have been studied from the kinetic point of view. Differential scanning calorimetry technique under non-isochronal conditions at various heating rates has been used to define the characteristic temperatures of the glasses (i.e. glass transition, crystallization) in addition to the glass stability parameters. The activation energies required for both the glass transition and amorphous to crystalline transformation have been computed by different methods. The mode of the glass crystallization has been determined in terms of the Avrami kinetic constant to identify the crystallization succession. Quantitative analysis of the thermal characteristics and kinetic parameters of the glass were achieved in terms of cross-linking density, number of bonds, and the bond stretching force. [ABSTRACT FROM AUTHOR]

Sm 3+ -doped oxyfluoride tellurite-tungsten (TWGSm) glasses were prepared by conventional melt quenching method. The optical properties were investigated through photoluminescence excitation, emission and luminescence decay analysis. The optical band gap energy was determined as ∼3.425 eV for 1.0 mol% of Sm 3+ -doped TWGSm glass. Upon 404 nm excitation, the TWGSm glasses emit luminescence through 4 G 5/2  →  6 H 5/2 (563 nm), 4 G 5/2  →  6 H 7/2 (600 nm), 4 G 5/2  →  6 H 9/2 (645 nm) and 4 G 5/2  →  6 H 11/2 (705 nm) transitions. The Judd-Ofelt analysis was performed using absorption spectrum and obtained radiative parameters were used to estimate the laser characteristics of present glasses. The concentration of Sm 3+ has been optimized as 1.0 mol% for efficient luminescence. The luminescence decay of 4 G 5/2 emission level was studied by monitoring the emission and excitation wavelengths at 600 and 404 nm, respectively. The experimental lifetime of 4 G 5/2 level was decrease with increase of Sm 3+ concentration. The 1.0 mol% of Sm 3+ -doped TWGSm glass could be the best choice for solid state visible lasers to emit orange luminescence. [ABSTRACT FROM AUTHOR]

The glass-forming domain and physical properties, namely, the density, thermal, structural and linear optical properties of new glasses within the TeO 2 -TiO 2 -WO 3 system have been investigated. By means of micro-Raman spectroscopy, the structure of these glasses was examined based on a full-scale spectral decomposition. The optical transmission and refractive index dispersion were measured by UV–Vis-NIR spectroscopy and spectroscopic ellipsometry respectively. Consistent correlations were established between the structural and linear optical properties. Only minor structural modifications of the original TeO 2 -rich network are taking place upon adding TiO 2 or WO 3 , suggesting the absence of Te–O–Te bond network depolymerization. Our results also suggest that, upon increasing TiO 2 content, a phase separation occurs between amorphous TeO 2 -rich and amorphous TiO 2 -rich regions. We also argue that the structural trends upon adding WO 3 evolve from uniformly dispersed WO 6 octahedra (at low WO 3 content) to amorphous WO 3 -like regions (at higher WO 3 content) before the crystallization of γ-WO 3 at 30 mol% of WO 3 . The compositional dependence of the refractive index and several optical constants (Urbach E U and dispersion E d energies, oxide ion polarizabilities) is highlighted. These glasses collectively exhibit high refractive indices in the order of ~2.2. [ABSTRACT FROM AUTHOR]

In this work, glasses in the MeO-PbCl 2 -TeO 2 (MeO = Bi 2 O 3 , MoO 3 , Sb 2 O 3 , WO 3 , ZnO) system, which show a great potential for optoelectronic applications, were used to evaluate their resistance under high energy ionizing radiations. The basic shielding quantities for determining the penetration of radiation in glass, such as mass attenuation coefficient (μ/ρ), half value layer (HVL), mean free path (MFP) and exposure buildup factor (EBF) values were investigated within the energy range 0.015 MeV ‒ 15 MeV using XCOM program and variation of shielding parameters were compared with different glass systems and ordinary concrete. From the derived results, it was determined that MeO-PbCl 2 -TeO 2 (MeO = Bi 2 O 3 , MoO 3 , Sb 2 O 3 , WO 3 , ZnO) glasses show great potentiality to be used under high energy radiations. Among the studied glass compositions, Bi 2 O 3 and WO 3 containing glasses were found to possess superior gamma-ray shielding effectiveness. [ABSTRACT FROM AUTHOR]

Er 3+ -doped phosphor-tellurite glasses has been synthesized by conventional melting method. Results of differential scanning calorimetry (DSC) measurements indicate a good thermal stability of tellurite glasses. The DSC measurements show an improvement of thermal stability of glass hosts after adding P 2 O 5 . The structures of glasses were investigated by X-ray diffraction (XRD) and Raman spectroscopy to understand their dependence of structure on composition. Absorption spectrum from near infrared to visible was obtained and the Judd–Ofelt (J-O) intensity parameters (Ω 2 , Ω 4 , and Ω 6 ) were determined. Spontaneous emission probabilities of some relevant transitions, branching ratio, and radiative lifetimes of several excited states of Er 3+ have been predicted using intensity J-O parameters. Up-conversion luminescence characteristics, under 977 nm excitation wavelength, have been investigated at room and low temperature in these glasses. Intense green and red emissions from Er 3+ centered at 534 nm, 548 nm and 660 nm, corresponding to the transitions 2 H 11/2 → 4 I 15/2 , 4 S 3/2 → 4 I 15/2 and 4 F 9/2 → 4 I 15/2 , respectively, were simultaneously observed. The quadratic dependence of the up-conversion emission on the excitation power indicates that two-photon steps are involved for the three visible emission bands. The PL lifetimes is found to decrease in the temperature range 77–300 K. Using the Mc-Cumber method, emission cross-section (σ e ), Absorption cross-section (σ a ), and gain cross-section (G(λ)) for the 4 I 13/2 → 4 I 15/2 transition, were calculated. By analyzing obtained data based to all advantages after adding P 2 O 5 , the tellurite glasses can be used as potential host material for developing optical amplifiers applied for 1.53 µm band broad and high-gain erbium-doped fiber amplifiers (EDFA). [ABSTRACT FROM AUTHOR]

The results of investigation of the impurity and phase inclusions as sources of non-selective losses in high-purity chalcogenide and tellurite glasses are reported. Extinction on the SiO 2 inclusions is shown to be responsible for non-selective losses in the chalcogenide glasses obtained by direct synthesis from elements in quartz equipment. Optimization of the temperature/duration conditions of the synthesis makes it possible to decrease these losses. The problem of achieving the theoretical minimum of optical loss in the glasses prone to crystallization is considered. The minimal scattering loss in such glasses can be limited not only by “freezing” fluctuations but also by the phase inhomogeneity of the glasses. A substantial contribution of the phase inclusions to optical losses is demonstrated on the example of high-purity tellurite glasses. The scattering in highly homogeneous samples of these glasses appears to be two orders of magnitude higher than the known theoretical value for scattering on “freezing” fluctuations. [ABSTRACT FROM AUTHOR]

The binary MoO 3 – TeO 2 glasses doped with 0–0.5 mol% of Ni 2 + ions were prepared by the melt-quenching technique using inorganic salts and acids as starting materials. The optical transmission spectra of all prepared glasses were studied in the wavelength range 0.5–6 μm. Two broad bands with maxima at 744 and 1318 nm are produced by octahedrally coordination nickel ions. The crystal field splitting energy and Racah parameters of Ni 2 + ions were calculated by using the Tanabe-Sugano diagrams. The spectral dependence of the specific absorption coefficient of nickel was established and the value of the integral absorption coefficient in the wavelength range 0.6–2.8 μm was found as (14.5 ± 0.3) cm − 2 /( ppmwt). The value of the optical band gap is observed to decrease while the refractive index and Urbach's energy increase with increase in the concentration of Ni 2 + in the glasses. [ABSTRACT FROM AUTHOR]

High-purity TeO 2 –ZnO, TeO 2 –ZnO–Na 2 O and TeO 2 –ZnO–La 2 O 3 –Na 2 O glasses have been characterized in terms of material applicability for magneto-optical devices. Glasses with extremely low content of absorbing impurities of 3d-transition metals and hydroxyl groups have been prepared inside a sealed silica glass chamber in a flow of purified oxygen. Magneto-optical properties, including spectral dependence of the Verdet constant in the 450–1561 nm range and magnetic figure of merit, crystallization stability and optical properties in the IR range were studied. [ABSTRACT FROM AUTHOR]

An understanding of the optical, thermal and structural properties of tellurite glasses is necessary for the development of new technological applications. Previous works have already been published studying the properties mentioned above, however, the mechanism of modification of the glassy structure due to the addition of rare earth ions is still an open topic in materials science. In this paper, we report the mechanisms of structural modification of the Er 3 + and Pr 3 + -doped glass tellurite-tungsten system through a systematic study. TeO 2 –ZnO–WO 3 –GeO 2 glasses codoped with Er 2 O 3 and varying the content of Pr 2 O 3 , was prepared by the conventional melt-quenching technique and studies of its structural, thermal and spectroscopic properties were carried out. The direct and indirect bandgap energies and the Urbach energy evidence an increase in the structural disorder of the glassy matrix due to the deformation of the Te O linkages by the insertion of Pr 3 + ions in the sample can be suggested. Raman spectroscopy results showed an increase in TeO 3 + 1 and TeO 3 compared to TeO 4 when the Pr 2 O 3 doping was increased, modifying the structural coordination in TeO 2 , generating non-bridging oxygens. Raman spectroscopy in low-frequencies shows the Boson peak changed with the increase in the concentration of Pr 3 +. Furthermore, was obtained that transverse modes predominate in low Raman frequencies. This work suggests that the presence of Pr 3 + ions influences the optical and thermal properties, in addition to altering the local glassy structure, generating a change in the coordination of network formers such as TeO 2. [ABSTRACT FROM AUTHOR]

• We modeled honeycomb-like multicore tellurite glass fiber network beam propagation. • We show how to obtain the best localized beam possible by changing structural parameters. • Randomization of the position of each core does not improve the localization of the beam. • Randomization of the size of each core improves the localization of the beam. • The best simulation obtained show a localized and stable beam pattern at z = 10 cm distance. In this paper, we have demonstrated by simulation that the transport of NIR optical images in a 10-cm-long all-solid tellurite optical fiber (wavelength of 1.55 µm) has a highly localized beam pattern by using a honeycomb structure with transversely pseudo-disordered fiber with random core sizes and fixed nearest-neighbor core-core center distance (core size between 1.0 and 1.4 µm and core-core center distance fixed at 3 µm). This paper shows the steps and different simulations used to obtain this structure with such a high beam localization. [ABSTRACT FROM AUTHOR]

• TWGEr glasses appear transparent, highly reflective and amorphous in nature. • Show deep-green emission through down conversion process at 377 nm excitation. • Exhibit intense green emission through up conversion process at 980 nm excitation. • Optimum concentration is 0.5 mol% for efficient green emission from TWGEr glasses. Different concentrations of Er3+ions doped TeO 2 -WO 3 -GeO 2 transparent oxyfluoride glassy materials were fabricated by conventional melt quench method and analyzed through X-ray diffraction, Fourier Transform infrared, scanning electron microscope and energy dispersive X-ray, photoluminescence-excitation, visible emission and luminescence decay studies. Various physical, structural, spectroscopic and laser characteristic parameters were evaluated following the Judd-Ofelt theory. The studied glasses were capable of emitting intense green luminescence through (2H 11/2 ,4S 3/2) → 4I 15/2 transitions. The emission of green luminescence was studied through down-conversion process at 377 nm excitation and up-conversion process at 980 nm excitation. The color coordinates were found to fall in the green region of chromaticity diagram and close to the European Broadcosting Union green illuminant. The evaluated branching ratio, stimulated emission cross-section, gain linewidth, figure of merit and the quantum efficiency corresponding to 4S 3/2 → 4I 15/2 transition suggests that the studied glasses find wide suitability to design green emitting solid state lighting devices. [ABSTRACT FROM AUTHOR]

The influence of adding Tm 2 O 3 in the tellurite-based glasses is analyzed through their physical, optical, structural, elastic, and gamma rays resisting features. The proposed glasses are prepared via the classic melt-quenching technique. As the Tm 2 O 3 concentration is raised (TeO 2 reduced), glass properties like density (ρ), and refractive index (n d) are elevated indicating an enhancement in the glass structure. Elastic constants were analyzed to rise with Tm3+ addition due to the production of bridging oxygens in the system. The elastic constants E, K, and G were perceived to rise with the Tm3+ concentration from 90.4 to 157 GPa, 131−156 GPa, 38.7−42.1 GPa. The μ values reduced from 244.14 t0 0.19 cm−1 (for the TmZT1 sample) and from 298.82 to 0.23 cm−1 (for TmZT5) when the γ-ray energy enriched between 0.015 and 15 MeV. And there is a good agreement between the MC simulated μ m values and the theoretically calculated XCOM μ m values. The difference (%) between both of the mentioned results is found in the range of ±2%. At γ ray energy of 0.662 MeV, as glass thickness increases, the radiation protection efficiency of each sample increases from 17.5 to 68.6% (for TmZT1), from 33.2 to 70.2% (for TmZT2), from 34.2 to 71.5% (for TmZT3), from 35.3 to 72.9% (for TmZT4), and from 36.4 to 74.3% (for TmZT5). • Thulium zinc-tellurite glasses were fabricated via melt-quenching technique. • The structural properties prove that the glasses are closely packed. • The elastic properties are increasing with the Tm 2 O 3. • RPE for all samples increases linearly with increasing the glass thickness. • A good agreement between MC simulated and theoretically calculated XCOM μ m values. [ABSTRACT FROM AUTHOR]

The melt and quench technique was used to create a new TeO 2 –Li 2 O–MoO 3 glass system with the objective of providing alternative and new shielding materials for radiation safety purposes. The synthesized glasses were studied by means of their physical, thermal, and radiation shielding characteristics. It was demonstrated using Raman and FTIR spectroscopy that the insertion of Li 2 O and MoO 3 resulted in a superimposed reduction of all Te units, including TeO 3+1 and TeO 3 with non-bridging oxygen, via the formation of Te(short)-O-Mo and a coordination change from MoO 4 to MoO 6. The densities of the prepared glasses were relatively high, having values between 4.48 and 5.11 g/cm3. Compared with TeO 2 -pure glass, the values for Tg and Tx substantially decrease with Li 2 O and MoO 3 insertion. However, among prepared samples, there is only a small fluctuation in both characteristic temperatures, suggesting high thermal/composition stability. FLUKA simulations were used to estimate the photon, proton, electron, α-particle, and carbon ion shielding parameters for beam energies ranging from 15 to 15,000 keV. With changes in the chemical designation of the synthesized glasses, the mass attenuation coefficient of photons and stopping powers of charged radiation changed, gradually increasing with glass density and decreasing with Li 2 O and MoO 3 insertion. In addition, the ability of the glasses to moderate fast neutrons declined with increases in the MoO 3 and Li 2 O weight contents. On the contrary, the total cross section of thermal neutrons improved as glass density decreased and Li 2 O and MoO 3 content increased. The synthesized glasses, through the evaluated parameters, showed better radiation shielding capacity compared to existing shields such as concrete and commercial RS-series glass shields. • New lithium/molybdenum tellurite glass system is designed and synthesized. • Thermal features are experimentally investigated. • Monte Carlo simulations is also carried out. • MoO 3 content plays an important role to evolve the present system. • TeLi–Mo1 glass system has a potential use in radiation applications. [ABSTRACT FROM AUTHOR]

Optical thermometers offer several advantages when dealing with fast response, stability against external factors and high thermal sensitivity. In this paper, tellurite glasses doped with Er3+-Yb3+ were fabricated by conventional melt-quenching technique. Absorption, luminescence under 380, 488 and 980 nm excitation and decay lifetime measurements were carried out to analyse the emission performance of the glasses. Two-photons process of the Er3+ emission in the visible region were confirmed by analysing the excitation power and up-conversion intensities under 980 nm. The temperature sensing was investigated under different excitation processes, both up-conversion and down-shifting, using the fluorescence intensity ratio technique on the 2H 11∕2 and 4S 3∕2 thermally coupled levels in the range of 93–348 K. These glasses exhibit an excellent thermal response and high thermal sensitivities, turning them into propitious candidates for optical fibre and thermal sensing applications. • Tellurite glasses doped with Er3+ and Yb3+ were synthesized with the melt-quenching technique. • The glasses were thermally and optically characterised. • The optical temperature sensing was studied using the FIR technique under different excitation processes. • High sensibilities were achieved with low Er3+ concentration. [ABSTRACT FROM AUTHOR]