Silica Fiber Research Articles

Combined Effect of Banana Fibre and Nano Silica on the Strength Properties of Concrete

Abstract: This study investigates the combined effect of nano silica and banana fibres on mechanical properties of concrete of grade M-25. Nano silica has been used as a partial replacement of cement by weight. Nano silica has been kept constant at 3% as maximum strength was achieved at this percentage according to past studies. Banana fibre has been added by weight of cement in proportions of 0.5%, 1%, 2%, 3%, 4% and 5%. Length of banana fibres kept at 40mm. Compressive strength was determined by using different combinations of nano silica and banana fibre. Nano concrete provides good strength as compared to conventional concrete. The addition of banana fibres in nano concrete improved the strength properties of nano concrete as well as improvement in crack resistance of concrete. On the other hand, the addition of banana fibres resulted in reduction workability as well as permeability of concrete

Formation of E-band luminescence-active centers in bismuth-doped silica fiber via atomic layer deposition.

In this study, a Si defect structure was added into the silica network in order to activate the bismuth and silica structure active center. TD-DFT theoretical simulations show that the Bi and Si ODC(I) models can excite the active center of the E-band at 1408 nm. Additionally, the Bi-doped silica fiber (BDSF) with improved fluorescence was fabricated using atomic layer deposition (ALD) combined with the modified chemical vapor deposition (MCVD) technique. Some tests were used to investigate the structural and optical properties of BDSF. The UV-VIS spectral peak of the BDSF preform is 424 cm-1, and the binding energy of XPS is 439.3 eV, indicating the presence of Bi° atom in BDSF. The Raman peak near 811 cm-1 corresponds to the Bi-O bond. The Si POL defect lacks a Bi-O structure, and the reason for the absence of simulated active center from the E-band is explained. A fluorescence spectrometer was used to analyze the emission peak of a BDSF at 1420 nm. The gain of the BDSF based optical amplifier was measured 28.8 dB at 1420 nm and confirmed the effective stimulation of the bismuth active center in the E-band.

Bandwidth extension to 1627 nm of over 20 dB gain in an erbium-doped silica fiber via two-photon absorption.

In this study, PbS/Er co-doped fibers (PEDFs) were fabricated by atomic layer deposition (ALD) combined with modified chemical vapor deposition (MCVD). A pumping scheme based on two-photon absorption at 1310 nm of PEDF is proposed for L + band amplification. Through the theoretical analysis, the local environment of Er3+ is changed due to the co-doping of PbS, which improves the two-photon absorption efficiency near 1300 nm. Compared with the 980 nm pump, the PEDFs excited by the 1310 nm pump show better amplification performance in the L + band. And in a bi-directional pumping system, PEDF achieves over 22 dB of gain in the whole L band. In particular, the bandwidth of over 20 dB gain was extended to 1627 nm with a noise figure as low as 4.9 dB. To the best of our knowledge, this is the first time that a high-gain bandwidth of L band amplification has been extended to 1627 nm. The results of unsaturated loss also show that PbS co-doping improves the two-photon absorption efficiency of PEDF to broaden the amplification bandwidth of L + band. These results demonstrate that an effective L + band amplification method is practically provided for future ultra-wideband optical communications.

New Progress on London Dispersive Energy, Polar Surface Interactions, and Lewis's Acid-Base Properties of Solid Surfaces.

The determination of the polar surface free energy, polar properties, and Lewis's acid base of solid materials is of capital importance in many industrial processes, such as adhesion, coatings, two-dimensional films, and adsorption phenomena. (1) Background: The physicochemical properties of many solid particles were characterized during the last forty years by using the retention time of injected well-known molecules into chromatographic columns containing the solid substrates to be characterized. The obtained net retention time of the solvents adsorbed on the solid, allowing the determination of the net retention volume directly correlated to the specific surface variables, dispersive, polar, and acid-base properties. (2) Methods: Many chromatographic methods were used to quantify the values of the different specific surface variables of the solids. However, one found a large deviation between the different results. In this paper, one proposed a new method based on the London dispersion equation that allowed the quantification of the polar free energy of adsorption, as well as the Lewis's acid-base constants of many solid surfaces. (3) Results: The newly applied method allowed us to obtain the polar enthalpy and entropy of adsorption of polar model organic molecules on several solid substrates, such as silica, alumina, MgO, ZnO, Zn, TiO2, and carbon fibers. (4) Conclusions: our new method based on the separation between the dispersive and polar free surface energy allowed us to better characterize the solid materials.

Single-photon generation from a neodymium ion in optical fiber at room temperature

The realization of single-photon generation is important for implementing various quantum information technologies. The use of rare-earth ions in an optical fiber is a promising single-photon generation method due to its ability to operate at room temperature as well as the low cost involved. Neodymium ions are especially interesting because the ions are one of the most commercially affordable rare-earth materials in the current industry. The neodymium ion also has the advantage of having a rich energy level structure, which offers several possible wavelengths for emitted single photons from visible to near-telecommunication wavelengths. In this paper, we experimentally demonstrated single-photon generation using an isolated single neodymium ion in tapered silica fiber at room temperature. Our results have significant implications as a platform for low-cost wavelength-selectable single-photon sources and photonic quantum applications.

Tree waste based advanced thermal insulation – Vacuum insulation panels – For application at up to 70 °C

Vacuum Insulation Panels (VIPs), despite being the best performing thermal insulation, face the challenges of high cost and environmental concerns associated with the core material, which typically consists of fumed silica (FS) or glass fibres. This study experimentally assessed the suitability of two novel core materials, which were generated from waste tree-based natural fibres (TNF), as potential substitutes for the expensive and widely used fumed silica. A series of composite samples were developed by mechanically mixing TNFs with FS and compressed to manufacture cores (150 mm × 150 mm). Samples were investigated for their radiative, gaseous and solid conductivities using extensive experimental techniques to identify the most cost-effective core composite for VIPs exposed to temperatures up to 70 °C. The spectral extinction coefficient of TNFs was determined by the use of Fourier Transform Infrared Spectroscopy and results indicated that TNFs exhibited a greater spectral extinction coefficient compared to fumed silica within the short infrared wavelength range of 2.5–7.5 μm. The radiative conductivity of fumed silica at a temperature of 70 °C was determined to be 3.33 mWm−1K−1, whereas the radiative conductivity of TNF composites varied between 0.53 mWm−1K−1and 0.39 mWm−1K−1. The VIP sample, which consisted of 100% FS material, had a thermal conductivity 7.84 mWm−1K−1 when measured at an average temperature of 20 °C. The observed value exhibited a substantial increase with the rise in temperature, reaching 11.58 mWm−1K−1 at a temperature of 70 °C. VIP containing 30 % tree-based natural fibre had the lowest thermal conductivity of 6.75 mWm−1K−1 and 8.28 mWm−1K−1 at 20 °C and 70 °C, respectively, among all composites studied. For this sample, VIP core material cost decreased from £3.46 kg−1 per R-value (100% FS) to £2.19 kg−1 per R-value at 20 °C. The study has concluded that a content of 30% of TNF is optimum for FS cores to deliver the most cost-effective VIP.

In-situ background-free Raman probe using double-cladding anti-resonant hollow-core fibers.

This study presents the development of an in-situ background-free Raman fiber probe, employing two customized double-cladding anti-resonant hollow-core fibers (AR-HCFs). The Raman background noise measured in the AR-HCF probe is lower than that of a conventional multi-mode silica fiber by two orders of magnitude. A plug-in device for fiber coupling optics was designed that was compatible with a commercially available confocal Raman microscope, enabling in-situ Raman detection. The numerical aperture (NA) of both AR-HCF claddings exceeds 0.2 substantially enhancing the collection efficiency of Raman signals at the distal end of the fiber probe. The performance of our Raman fiber probe is demonstrated by characterizing samples of acrylonitrile-butadiene-styrene (ABS) plastics, alumina ceramics, and ethylene glycol solution.

Observation of Visible Upconversion Luminescence of Soft Glass Multimode Fibers

This research investigates the visible upconversion luminescence which is induced by multiphoton absorption of soft glass fiber defects. The study of this phenomenon has thus far been restricted to standard silica fibers. We observed the emission of green and cyan light as a consequence of fiber material ionization. We investigate both the commercial ZBLAN step index and in-house-made tellurite nanostructured graded-index fibers. For the latter, the analysis of the luminescence signal permits us to determine the core and cladding refractive index difference. Upconversion luminescence is a powerful tool for characterizing soft glass fibers and a promising platform for innovative photonic technologies and mid-IR applications.

Quantum storage of 1650 modes of single photons at telecom wavelength

To advance the full potential of quantum networks one should be able to distribute quantum resources over long distances at appreciable rates. As a consequence, all components in such networks need to have large multimode capacity to manipulate photonic quantum states. Towards this end, a photonic quantum memory with a large multimode capacity, especially one operating at telecom wavelength, remains an important challenge. Here we optimize the preparation of atomic frequency combs and demonstrate a spectro-temporally multiplexed quantum memory in a 10-m-long cryogenically cooled erbium doped silica fibre. Our multiplexing storage has five spectral channels - each 10 GHz wide with 5 GHz separation - with up to 330 temporal modes in each, thus resulting in a simultaneous storage of 1,650 modes of heralded single photons with a 1000-fold increasing in coincidence detection rate with respect to single mode storage. Our results could pave the way for high speed quantum networks compatible with the infrastructure of fibre optical communication.

Flexible Copper-Doped Silica Fibers Promote Infected Conjunctival Tissue Repair Through Antibacterial and Anti-inflammatory Effects

Flexible Copper-Doped Silica Fibers Promote Infected Conjunctival Tissue Repair Through Antibacterial and Anti-inflammatory Effects

Multi-point calorimeter using distributed fiber Bragg gratings for small field dosimetry in radiotherapy.

The interest of using fiber Bragg gratings (FBGs) dosimeters in radiotherapy (RT) lies in their (i) microliter detection volume, (ii) customizable spatial resolution, (iii) multi-point dose measurement, (iv) real-time data acquisition and (v) insensitivity to Cherenkov light. These characteristics could prove very useful for characterizing dose distributions of small and nonstandard fields with high spatialresolution. We developed a multi-point FBGs dosimeter customized for small field RT dosimetry with a spatial resolution of 1mm. The 3cm-long multi-point dosimeter is made by embedding a 80 silica fiber containing an array of thirty (30) co-located 1mm-long fs-written FBGs inside a plastic cylinder with an UV curing optical adhesive. With its higher thermal expansion coefficient, the plastic cylinder increases the sensitivity of the dosimeter by stretching the fiber containing the FBGs when the temperature rises slightly due to radiation energy deposition. Irradiations (2000MU at 600MU/min) were performed with a Varian TrueBeam linearaccelerator. The dose profile of a 2 2cm 6MV beam was measured with a mean relative difference of 1.8% (excluding the penumbra region). The measured output factors for a 6MV beam are in general agreement with the expected values within the experimental uncertainty (except for the 2 2cm field). The detector response to different energy of photon and electron beams is within 5% of the mean response ( pm/Gy). The calorimeter's post-irradiation thermal decay is in agreement with thetheory. An energy-independent small field calorimeter that allows dose profile and output factor measurements for RT using FBGs was developed, which, to our knowledge, has never been done before. This type of detector could prove really useful for small field dosimetry, but also potentially for MRI-LINAC since FBGs are insensitive to magnetic fields and for FLASH since FBGs have been used to measure doses up to100kGy.

Thermomechanical performance and multiscale modeling of hexagonal boron nitride modified out-of-autoclave manufactured silica fiber reinforced phenolic composites

In this study, high loadings of boron nitride (BN) nanoplatelets were added to silica fiber-reinforced phenolic composites to study the multifunctional impact of BN loading and manufacturing processing on the subsequent mechanical, thermal, and thermomechanical properties. A series of high-quality laminates were made with various loadings of BN using compression-molded out-of-autoclave processing. Three-point bend and short beam shear testing determined the relationship between BN loading and mechanical performance. The fracture properties were analyzed using optical and scanning electron microscopy. The thermal conductivity performance was increased up to a 93% improvement, indicating the thermal management multifunctionality of the modified composites without changing the crosslinking ability or glass transition temperature significantly. The modified performance of hybrid silica/phenolic/BN composites is demonstrated through micromechanical multiscale modeling, where BN loading and particle stress concentrations impact the modulus and strength of the composite.

High-power tunable Raman soliton generation in large core diameter passive fibers via a precise fundamental-mode matching technique.

We demonstrate tunable high-power, high-energy Raman solitons with the range of 1.9-2.3 µm in large mode area (LMA) fibers and an optimized fundamental-mode matching technique for coupling LMA silica fibers. Finally, we obtained Raman solitons with a maximum output power of 5.8 W and a maximum pulse energy of 105 nJ in a LMA passive fiber with 32 µm core diameter, the tuning range of Raman soliton is 1.96-2.35 µm. In addition, we obtained Raman solitons with a maximum output power of 7.3 W and a maximum pulse energy of 126 nJ in a LMA passive fiber with 48 µm core diameter, the tuning range of Raman soliton is 1.96-2.27 µm. The output power of 7.3 W is the highest Raman soliton power currently available in silica fibers, and the result fills a gap in the generation of both high-power and high-energy Raman solitons in a LMA silica fiber.

Evaporation characteristics of Er3+-doped silica fiber and its application in the preparation of whispering gallery mode lasers.

In this work, the concentration of rare-earth ions in doped silica whispering gallery lasers (WGLs) is controlled by evaporation. The fabrication of WGLs is used to experimentally evaluate the evaporation rate (mol/μm) and ratio (mol/mol) of erbium and silica lost from a doped fiber during heating. Fixed lengths of doped silica fiber are spliced to different lengths of undoped fiber and then evaporated by feeding into the focus of a CO2 laser. During evaporation, erbium ions are precipitated in the doped silica fiber to control the erbium concentration in the remaining SiO2, which is melted into a microsphere. By increasing the length of the undoped section, a critical point is reached where effectively no ions remain in the glass microsphere. The critical point is found using the spectra of the whispering gallery modes in microspheres with equal sizes. From the critical point, it is estimated that, for a given CO2 laser power, 6.36 × 10-21 mol of Er3+ is lost during the evaporation process for every cubic micron of silica fiber. This is equivalent to 1.74 × 10-7 mol of Er3+ lost per mol of SiO2 evaporated. This result facilitates the control of the doping concentration in WGLs and provides insight into the kinetics of laser-induced evaporation of doped silica.

Numerical Study of Early Detection of Tuberculosis Infected with High Sensitivity Plasmonic Sensor

In this work, a photonic crystal fiber based on a plasmonic sensor for the early detection of tuberculosis has been designed with finite element analysis. The component is constructed with a substrate layer made of fused silica material, which is then coated with a thin film of TiO2 layer as an adhesive layer to strongly attach the Au layer with the silica fiber surface. The TiO2 layer has an optimal thickness of 45 nm, while the Au layer has a thickness of 50 nm. The sensor design has a refractive index (RI) detection range from 1.27 RIU to 1.37 RIU, it also shows a maximum wavelength sensitivity (WS), maximum amplitude sensitivity (AS), sensor resolution (SR), and sensor accuracy (SA) of 20,000 nm/RIU (x-polarized) and 17.000 nm/RIU( y-polarized), -211.38 1/RIU (x-polarized) and -211.211 1/RIU (y-polarized), 9.17 x 10−5 RIU (x-polarized) and 1 x 10−4 RIU (y-polarized), and 0.025/nm respectively. Tuberculosis exhibits a normal and infected RI range of 1.343 RIU to 1.351 RIU. Therefore, the proposed sensor design is capable of detecting four types of TB infections with high sensitivity.

From fundamental materials chemistry to sensing applications: Unravelling the water adsorption mechanism of a luminescent optical fibre sensor membrane

This work provides insight into the correlation between the luminescent response of a water-vapour optical fibre sensor and the textural properties of its lanthanide-doped silica coating. To this end, a library of 16 silica xerogels derived from combinations between 2 lanthanide dopants (EuIII, TbIII) and 8 antenna ligands was synthesised and characterised by photoluminescence spectroscopy and N2 and CO2 adsorption-desorption isotherms, among others. Based on the best luminescent response and most-suited porous texture, the material doped with TbIII and 2,2′-(4-(2-Ethoxyethoxy)pyridine-2,6-diyl)bis(4,5-dihydrooxazole) was selected to construct the probe. A film of this material was affixed to a commercial silica fibre by dip-coating and the resulting sensor was tested in a climatic chamber with relative humidity ranging from 20 to 90% to obtain normalised time-response and calibration curves at three temperatures. The response was linear up to certain water-vapour concentrations, beyond which abruptly changed to polynomial, acting against the sensor resolution. The adsorption mechanism was elucidated by comparing the isosteric enthalpies of adsorption calculated from the sensor calibration curves to those determined from the monolith water-vapour isotherms, revealing that capillary condensation in the membrane mesopores was the key phenomenon leading to the response deviating from linearity.

Generation of infrared photon pairs by spontaneous four-wave mixing in a CS2-filled microstructured optical fiber

We experimentally demonstrate frequency non-degenerate photon-pair generation via spontaneous four-wave mixing from a novel CS2-filled microstructured optical fiber. CS2 has high nonlinearity, narrow Raman lines, a broad transmission spectrum, and also has a large index contrast with the microstructured silica fiber. We can achieve phase matching over a large spectral range by tuning the pump wavelength, allowing the generation of idler photons in the infrared region, which is suitable for applications in quantum spectroscopy. Moreover, we demonstrate a coincidence-to-accidental ratio of larger than 90 and a pair generation efficiency of about 10-2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$10^{-2}$$\\end{document} per pump pulse, which shows the viability of this fiber-based platform as a photon-pair source for quantum technology applications.

Fiber Optic Vacuum Ultraviolet Sensor Based on an AlN-Microwire Probe

Vacuum ultraviolet (VUV) light sensing shows great potential applications in the space science, materials, biophysics, and plasma physics. In this work, an all-optical detection method is proposed for VUV sensing by constructing an optical fiber-end Fabry-Pérot interferometer based on a single aluminum nitride (AlN) microwire. Compared with the traditional electrical devices, this all-optical detection method overcomes the difficulties like the fast response and electromagnetic interference immunity in detecting VUV bands at the present stage, and improves the response speed. The proposed device shows the excellent performance of VUV detection, with the static sensitivity of 1.03 nm/(W·cm−2), response rise time of down to 10 µs, and decay time of 0.64 ms. Beneficial from the excellent radiation resistance of AlN microwires and UV resistance of silica fibers, the proposed device is expected to have the good stability and potential applications in the fields of the solar physics and space exploration.

Effect of X-Ray Radiation and High Temperature on Long Period Fiber Gratings in Crystal-Derived Silica Fiber

Effect of X-Ray Radiation and High Temperature on Long Period Fiber Gratings in Crystal-Derived Silica Fiber

Actively pulse shaped linearly polarized nanosecond hybrid Ho3+ and Tm3+-doped silica fiber & Ho3+:YAG MOPA at 2048 nm

Ho3+:YAG amplifiers are able to efficiently scale pulse energy at wavelengths far shorter than the main emission peak. For 24 W input power at 2048 nm a signal output power of 81.6 W is reached, resulting in 5.3 dB gain.