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A system of bio-silica borotellurite glasses was fabricated based on the chemical formula [(TeO2)0.7 (B2O3)0.3]1-x (SiO2)x with x = 0.1, 0.2, 0.3, and 0.4 using the melt-quenching technique using silica (98.548% SiO2, from rice husk), TeO2 (Alfar Aeser, 99.9%) and B2O3 (Alfar Aeser, 99.9%). Measurements and characterizations such as density and molar volume measurements, XRD analysis, FTIR, and UV–Vis spectroscopes were performed on the studied glasses. The objective was to determine the glasses’ applicability in optoelectronics, non-linear optics, and laser technologies through polarizability, linear electric susceptibility, and optical basicity study. Apart from confirming the amorphous nature of the glasses, the XRD analysis identified the presence of a crystalline phase of tellurium oxide (α-TeO2) formed. The FTIR spectral study revealed the presence of TeO3, BO3, and SiO4 structural units in the studied glasses. The refractive index (2.3026 – 2.2651), molar polarizability (8.0696 – 9.4334 A3), oxide ion polarizability (3.2970 – 3.6202 A3), electronic polarizability (0.2296 – 0.2335 A3), dielectric constant (5.1307 – 5.3019), optical basicity (0.6719 – 0.7998), metallization criterion (0.410853 – 0.420714) and electric susceptibility (0.3286 – 0.3422 esu) of the glasses were presented. With the high refractive index and favourable electronic/oxide ion polarizability as well as good electric susceptibility, the glasses have shown great potential for optical fibre and laser applications. Metallization criterion value falls in the range of glasses with great potentials for non-linear optical application. The dielectric value suggests the glasses represent wideband semiconducting glasses believed to be good for application in microelectronic substrates fabrication.

New glass samples with composition (1 – x)[(TeO2)70(B2O3)30] – x(Gd2O3) with x = 0.2, 0.4, 0.6, 0.8 and 1.0 in mol% have been synthesized by conventional melt-quenching techniques. X-ray diffraction (XRD) studies were performed in order to confirm the amorphous nature of the samples. The density of the samples has been found to vary with the Gd2O3 content, whereas an opposite trend has been observed in the molar volume. The analysis of Fourier Transform Infrared (FT-IR) spectroscopy of the samples showed that the glass network is mainly built of TeO3, TeO4, BO3 and BO4 units. The addition of Gd2O3 changed the refractive index, optical band gap and Urbach energy of the glass samples. The thermal properties of the studied glasses were investigated by measuring the thermal diffusivity of the samples by using photoflash method at room temperature.

Erbium nano particles (NPs) doped tellurite glasses were prepared via melt-quenched technique and their chemical composition are as follows; {[(TeO2) 0.70 ( B 2 O3) 0.30 ] 0.7 (ZnO) 0.3 } y (Er2O 3 NPs) 1−y , y = 0.005, 0.01, 0.02, 0.03, 0.04 and 0.05. The amorphous state of the glass system was revealed and the structural parameters indicating the formation of non-bridging oxygen was shown. The current work underlines the spectral parameters from Judd–Ofelt (JO) studies, and upconversion spectra. The existence of erbium NPs was found experimentally using transmission electron microscopy (TEM). The Judd–Ofelt analysis suggests that the radiative probability, A rad is strong at 2H 11∕2 —> 4I 15∕2 and a longer lifetime at 4I 11∕2 —> 4I 15∕2 . The Argon laser beam was used to determine the upconversion emission peaks. The upconversion radiation emission excited at 800 nm was found in the range 390 nm.

In this study, the optical and gamma ray shielding properties of vanadotellurite-based quaternary glasses in the xNa2O-(20-x)K2O-30V2O5-50TeO2 system were examined. The optical band gap ( E opt ) displayed an initial reduction from 2.33 to 2.30 eV (x ≤ 10 mol%), before increasing from 2.31 to 2.39 eV for x > 10 mol%, which indicated a change in non-bridging oxygen (NBO) concentration. There is an inverse relationship between Urbach energy ( E u ) and E opt . The refractive index (n) also showed an off-trend pattern within the same area (x = 10 mol%), which indicated a difference in polarizability due to changes in BO and NBO concentrations. The Phy-X software was used to analyse the radiation attenuation competence for the investigated glass systems. For the total interaction of photons between the 0.284 to 2.506 MeV energy range, the linear attenuation coefficients (LAC), the radiation protection efficiency (RPE), half-value layers (HVL) and mean free path (MFP) were determined. The increased Na2O content increased the values of LAC and RPE. The results demonstrated that the 20Na2O-30V2O5-50TeO2 composition had the most desired photon shielding properties.

The main problem of commercial silicate glass fiber is its high-loss and weak optical efficiency. It is very important to produce non-silicate glass fiber with low-loss and high optical efficiency. In this work, low-loss and high optical efficiency of Nd3+ nanoparticles doped borotellurite glass had been produced. The analysis of FTIR spectra shows the presence of functional vibration of tellurite network. The refractive index of borotellurite glass was enhanced in between 1.947 and 2.045 with the increment of Nd3+ nanoparticles. Several excitation bands within UV–Vis range due to the effect of Nd3+ nanoparticles was perceived originating from the ground state 4I9/2 to the excited states 2P3/2, 4G7/2, 4G5/2, 4F9/2, 4F7/2, 4F5/2 and 4F3/2. The glass system shows tendency towards semiconducting behavior as the value of Fermi energy, EF decreases. The high intensity of red emission was found from Nd3+ nanoparticles doped borotellurite glass. Hence, this Nd3+ nanoparticles doped borotellurite glass has immense potential for the development of fiber amplifiers and lasers. Keywords: Borotellurite glass, Neodymium nanoparticles, Rare-earth oxide

Neodymium oxide doped tellurite-based glass has been widely documented for potential uses in optoelectronics, but graphene oxide (GO)-coated tellurite-based glass has rarely been reported. In this work, we compare two sets of glass series which were GO-coated and uncoated tellurite-based glass series denoted as ZBTNd-GO and ZBTNd, respectively. The two sets of glasses were fabricated via melt-quenched process. A set of glass was coated with GO using low-cost spray coating method. The structural and morphological properties of the glass samples were investigated to confirm the type of structure in glass and formation of graphene oxide on glass surface. The X-ray diffraction (XRD) pattern confirmed the amorphous structural arrangement in both sets of glass series. The morphological study proved the existence of GO layers on top of the ZBTNd-GO surface. The optical bandgap energy of ZBTNd-GO glass was found in the range of 3.253 eV–3.381 eV which was higher than ZBTNd glass. Meanwhile, the refractive index of ZBTNd-GO glass varies from 2.301 to 2.332 which was higher than ZBTNd glass due to the presence of functionalized oxygenated groups in GO structure. The oxide ion polarizability of ZBTNd-GO glass was found decreased due to the shift of optical band gap when coated with GO. This work offers a new form of glass that could be used as a new strategy to upgrade the current photonic materials.

Judd–Ofelt (J–O) theory was used to analyze the optical properties of erbium (Er3+) ions doped zinc-sodium-tellurite glass system incorporated with titania (TiO2) nanoparticles (TNPs) for the realization of up-converted solid state lasers. Such glass systems were synthesized using melt quenching method to determine the influence of varying TNPs contents on the absorption and emission properties. J-O intensity parameters (Ω2, Ω4, Ω6), spectroscopic quality factor (χ = Ω4/Ω6), radiative transition probabilities, branching ratio, and radiative lifetime of various transitions involved in the Er3+ ions were calculated from the measured optical spectra. XRD pattern verified the amorphous nature of the prepared glass samples. TEM images manifested the growth of TNPs inside the glass matrix having mean size between 15 and 25 nm. UV–Vis–NIR spectra exhibited ten absorption bands centred at 407, 444, 452, 489, 522, 552, 653, 800, 976 and 1532 nm. Two surface plasmon resonance (SPR) bands of TNPs were evidenced at 552 nm and 580 nm. Luminescence spectra revealed three prominent peaks centred at 525, 545 and 660 nm, where the glass sample containing 0.2 mol% of TNPs displayed optimum intensity enhancement by a factor of 30.00, 28.57 and 19.60, respectively. This enhancement is primarily attributed to the TNPs surface plasmon enabled colossal localized electric field in the proximity of Er3+ ions and subsequent energy transfer to the Er3+ ions. Values of Ω2, Ω4, Ω6 and χ were ranged between (2.14−3.72)×10−20, (1.27−2.77)×10−20, (1.42−2.22)×10−20 cm2 and (0.58–1.94), respectively. Occurrence of higher values of Ω2 and Ω6 indicated the existence of lower symmetry and stronger covalency around the Er3+ ions. Furthermore, the decrease of χ values with increasing TNPs up to 0.2 mol% approved intensified lasing transition. Achieved higher values of Ω4 and Ω6 demonstrated that the present glass composition is a prospective lasing media.

The aim of this work is to determine the effect of Nd3+ ion concentration on the elastic properties of zinc-tellurite glass for the development of waveguide lasers. A series of Neodymium doped zinc-tellurite (NZT) glass system of composition [(TeO2) 0.70 (ZnO) 0.30] (1-x) Nd2O3 (x), x =0, 0.01, 0.02, 0.03, 0.04 and 0.05, were synthesized by using conventional melt-quenching method. XRD analysis confirmed the amorphous nature of the glass; the FTIR confirmed the presence of TeO3 and TeO4 in the glass network. The density of the glass system increases with increase in neodymium concentration. The longitudinal ultrasonic velocity decreases from 3737.01 to 3045.23 ± 10 ms−1, and the shear velocity decreases from 1959.31 to 1887.81 ± 10 ms−1. The experimental results have shown that the elastic properties depend on the composition of the glass systems and the effect of neodymium (Nd2O3) within the glass network.

A glass series of erbium doped zinc borotellurite glass system was prepared by using the melt-quenching method. The absorption spectra revealed several bands at visible range which correspond to the following transitions (from the ground state); 4G11/2 + 2H9/2 + 4F5/2 + 4F7/2 + 2H11/2 + 4S3/2 + 4F9/2 + 4I9/2 + 4I11/2. From the Judd–Ofelt analysis, it is found that the trend of Ω2 values is a non-linear variation along with erbium concentrations. Meanwhile, the value of Ω6 decreases as the erbium concentration increases. The photoluminescence analysis shows green emission which are attributed to the 4S3/2 level to the ground state at 4I15/2. Meanwhile, the upconversion analysis revealed several emission bands at 376 nm, 424 nm, 470 nm and 558 nm which correspond to 4G11/2 → 4I15/2, 4F3/2 → 4I15/2, 4F7/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions respectively. The non-linear refractive index spectra show self-defocusing behavior and negative nonlinear refraction (ƞ2

Zinc borotellurite glasses doped with lanthanum oxide were successfully prepared through melt-quenching technique. The amorphous nature of the glass system was validated by the presence of a broad hump in the XRD result. The refractive index of the prepared glass samples was calculated by using the equation proposed by Dimitrov and Sakka. The theoretical value of molar refraction, electronic polarizability, oxide ion polarizability and metallization criterion were calculated by using Lorentz-Lorenz equation. Meanwhile, expression proposed by Duffy and Ingram for the theoretical value of optical basicity of multi-component glasses were applied to obtain energy band gap based optical basicity and refractive index based optical basicity. The optical basicity of prepared glasses decreased with the increasing concentration of lanthanum oxide. Metallization criterion on the basis of refractive index showed an increasing trend while energy band gap based metallization criterion showed a decreasing trend. The small metallization criterion values of the glass samples represent that the width of the conduction band becomes larger which increase the tendency for metallization of the glasses. The results obtained indicates that the fabricated glasses have high potential to be applied on optical limiting devices in photonic field. Keywords: Borotellurite glasses, Refractive index, Electronic polarizability, Oxide ion polarizability, Optical basicity, Metallization criterion

Comparative analysis on optical properties between two glass series (a—ordinary glass, b—glass with nanoparticles) have been estimated. The two glass series (a—ordinary glass, b—glass with nanoparticles) with compositions {[(TeO2)0.70 (B2O3)0.30]0.70 (ZnO)0.30}1−y (Er2O3/Er2O3 nanoparticles)y; y = 0.005, 0.01, 0.02, 0.03, 0.04, 0.05 mol% were successfully prepared by using melt-quenching method. The TEM, EDX and XRD have been used to confirm the existence of nanoparticles and all elements in the glass system. The density of b—glass with nanoparticles are found greater than a—ordinary glass. The optical properties of the glass series were characterized by using Ellipsometer and UV–Vis spectrophotometer. There is a linear increasing trend in refractive index of the glass series along with concentration of erbium and erbium nanoparticles oxide. The refractive index of b—glass with nanoparticles is greater than a—ordinary glass. Moreover, the absorption peaks of a—ordinary glass are more intense than b—glass with nanoparticles. The glass with nanoparticles will offer a potential materials for nanophotonic devices.

The glass series of samarium nanoparticles (NPs) doped zinc borotellurite glasses were successfully fabricated by using conventional melt-quenching technique. The structural properties of the prepared glasses were investigated by X-ray diffraction (XRD) analysis and FTIR analysis. It was confirmed that the prepared glasses are amorphous in nature. The bonding parameters of the glasses were analyzed by using FTIR analysis and were found the formation of non-bridging oxygen. The density of these glasses were measured and found to be increased with increasing samarium NPs content. The optical absorption spectra of these glasses were revealed that the fundamental absorption edge shifts to higher wavelengths as the content of Sm2O3 (NPs) increases. The optical energy band gap are found to be decreased linearly with an increasing samarium NPs concentration which is due to the formation of non-bridging oxygen in the glass system.KeywordsBorotellurite glass; optical band gap, Samarium nanoparticles.

Neodymium doped zinc borotellurite glass system were fabricated by using conventional melt-quenching method. The structural properties of the glass system were characterized by using X-ray Diffraction (XRD) method and Fourier Transform analysis (FTIR). The amorphous nature of the glass system was confirmed by using x-ray diffraction method. The transmission band of TeO3 structural units which indicate the existence of non-bridging oxygen was shown by FTIR analysis. The optical properties of the glass system were determined by using UV-Vis spectrophotometer. Several bands were shown in the absorption spectra which indicate the characteristic of neodymium ions. The obtained values of indirect optical band gap, Eopt lies in the range of 3.151 eV and 3.184 eV.

In this work, linear and nonlinear optical parameters of zinc borotellurite glasses doped with Gd3+ have been studied for all-optical switching applications. A series of gadolinium zinc borotellurite glasses were synthesized by using conventional melt quenching technique. Optical absorption spectra were recorded by UV–vis spectroscopy. From the optical absorption spectra, the cut-off wavelength, optical band gap, Urbach energy and refractive index have been determined and are related to the structural changes in the glass systems. The nonlinear optical properties of Gd3+ doped glasses are investigated by using Z-scan technique. The values of nonlinear refractive index and absorption coefficient with closed and opened apertures of the Z-scan, respectively, were determined for proper utilization in nonlinear optical devices. Keywords: Gadolinium, Rare earth, Borotellurite glass, Optical band gap, Refractive index, Nonlinear optical properties

Efficient, inexpensive and eye−safe new host glass as up−conversion (UC) emission solid−state laser media became demanding. Nanoparticles (NPs) of various noble metals have been inserted into the phosphate−based amorphous host matrix to enhance the rare-earth ions (REIs) stimulated emission cross−section. Furthermore, only a few reports exist on the combined influences of neodymium ions (Nd3+) and pure silver (Ag) NPs on the structural and optical response of magnesium zinc sulfophosphate (MZSP) glasses. In this view, a series of MZSP glasses were doped by Nd3+ ions and pure Ag NPs (at different concentrations) to improve their structural and optical properties. Such melt−quench synthesized glasses were characterized at room temperature using diverse analytical measurement tools. The XRD pattern of as−quenched samples approved their amorphous nature. The FTIR and Raman spectra of glasses revealed the presence of characteristic bonding vibrations of different functional groups. The TEM images showed the existence of spherical Ag NPs (mean size of 8.34 nm) in the host glass matrix. The surface plasmon resonance (SPR) band of Ag NPs was detected around 451 nm. The UV–Vis–NIR absorption and PL emission spectra of glasses were utilized to evaluate the Judd−Ofelt (JO) intensity parameters ( Ω 2 , Ω 4 and Ω 6 ) and radiative properties. The observed fluctuation in the Ω 2 values with the increase in Ag NPs contents was attributed to the dynamic change of ligands symmetry around Nd3+ inside the glass network. Variations in the Ω 4 and Ω 6 values with the increase in Ag NPs contents indicated a considerable reduction in the glass rigidity. The PL spectra of glasses exhibited a prominent band around 576–584 nm corresponding to the 2G7/2 +4G5/2 → 4I9/2 transition in Nd3+. Glass prepared with 0.5 mol% of Ag NPs disclosed the highest PL enhancement (≈19 times) and largest emission cross−section (≈4.35 × 10−24 cm2) which was ascribed to the synergism between Ag NPs SPR mediated strong local field effect (LFE) and the subsequent energy transfer to Nd3+ appeared in the proximity of NPs. It was concluded that the proposed glass composition can lead to the development of UC solid−state laser compared to many other reported glass system.

In this work, we synthesize graphene oxide (GO)-coated tellurite glass for the improved optical performance of fiber optics. A series of tellurite glass system with composition of {[(TeO2)0.7 (B2O3)0.3]0.7 (ZnO) 0.3}1-y (Er2O3) y where y (mol%) = 0.005, 0.01, 0.02, 0.03, 0.04and 0.05 mol% was successfully fabricated and coated with GO by using melt-quenching and spray coating methods. The structural properties were characterized by using XRD analysis and FESEM. The XRD patterns indicated that the tellurite glass were amorphous. The FTIR transmissions images revealed the surface morphology of GO on the glass surface. The optical band gap energy was found enhanced from 3.392 to 3.495 eV. The refractive index was found improved from 2.275 to 2.299 with the existence of GO. Hence, these results were useful for the application of fiber optics.

A series of neodymium NPs doped tellurite glass with composition of (TeO2)0.7(B2O3)0.3]0.7 (ZnO)0.3}1- x (Nd2O3 NPs) x (x = 0.005, 0.01, 0.02, 0.03, 0.04 and 0.05 mol%) was fabricated via melt-quenching method. Density and molar volume were measured and analyzed for the glass series. The optical properties of neodymium NPs doped tellurite glass were measured by UV–Vis spectrometer, photoluminescence and Z-scan technique. The optical band gap energy of the glass network was in the range of 3.178–3.209 eV. The upconversion emission of the laser glass excited at 800 nm was found in the ultraviolet region. Electronic polarizability, oxide ion polarizability, optical basicity and metallization criterion were calculated. Moreover, linear absorption coefficient, α, nonlinear refractive index ƞ (cm2/W), nonlinear absorption, β (x 10−3) and third order susceptibilities, χ (x 10−6) were measured. The optical efficiency of neodymium NPs doped tellurite glass exhibited excellent properties for its application in laser glass.

Successful extraction of high purity SiO2 (about 99%) from rice husk (waste) was achieved in this work using the cold acid leaching method. Glass series [(TeO2)0.7 (B2O3)0.3]1-x (SiO2)x were fabricated using the rice husk silicate (RHS) by melt-quenching method. The samples were subjected to X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) characterization to study the structural nature of the glass system. Density and ultrasonic velocities were measured to obtain the elastic constants for the various silicate proportions in the glass using ultrasonic data obtained from non-destructive ultrasonic probing technique. The elastic moduli calculated from the obtained data were found to have increased with the addition of more RHS in the glass. Other parameters studied include the microhardness (H), Poisson's ratio (σ), softening temperature (ϴD) and fractal bond connectivity (d) and the fluctuation free volume (fugacity, fg). A very unusual occurrence was observed as microhardness value decreases in the glass system as more RHS (SiO2) is introduced. The quality of the glass in terms of elastic behavior improved with addition of RHS in the borotellurite glass network.

The glass series with composition of {[(TeO 2 ) 0.70 (B 2 O 3 ) 0.30 ] 0.7 (ZnO) 0.3 } 1-y (Nd 2 O 3 ) y where, y = 0.005, 0.01, 0.02, 0.03, 0.04 and 0.05; was fabricated via melt-quenched technique. The third-order optical nonlinearity was observed by using Z-scan technique. Polarizability and third-order nonlinearity of borotellurite glass doped with neodymium (Nd 3+ ) will be reported. This work presents the effect of neodymium ions on the linear and nonlinear optical performance of borotellurite glass for potential photonics applications. The structure and optical performance of the resulting transparent neodymium doped borotellurite glass are characterized. The reduction of optical band gap energy, E g is observed which shows the alteration of tellurite structure by the Nd 3+ . The values of electronic polarizability are enhanced with an increase of Nd 3+ ions. The enhancement of electronic polarizability provides an excellent medium for nonlinear optical applications. The optical basicity of the investigated materials shows non-linear trend along with Nd 3+ ions concentration. The Z-scan data for third-order optical nonlinearities suggest that the glass materials are excellent to be used as a medium in nonlinear optical fiber. Therefore, the investigated glass materials may provide a good material for photonic applications.