Glass Refractive Index Research Articles

The Effect of Calcium Fluoride in Lithium Phosphate Oxide (LPO) Doped with Sm3+ Content

This work will present the effect of calcium fluoride in lithium phosphate oxide glass. The glass compositions based on 69 P2O5–20Li2O–10Al2O3–1Sm2O3 and 59 P2O5–20Li2O–10Al2O3–10CaF2–1Sm2O3 are prepared by melting and quenched technique. The physical, structural, optical, and spectroscopic properties have been investigated to determine the performance of calcium fluoride on lithium phosphate oxide glass. The density and refractive index of glass without CaF2 have higher values compared to glass added with CaF2. The FTIR spectrum showed the reduction of the O-H group in a glass added with CaF2. The absorption band of Sm3+ ions start from 6H5/2 as the ground state in the UV-Vis-NIR region. The spectroscopic properties of the glasses have been obtained by using J-O analysis.

Judd-Ofelt and McCumber Studies of Er3+ Ions Doped in Lanthanum Borate Glass for Visible and NIR Lighting Application

The lanthanum borate glasses doped with Er3+ were prepared by the melt-quenching technique to study the physical and luminescence properties. The glass composition in this study is 27.5La2O3-(72.5-x)B2O3-xEr2O3, where x = 0, 1, 2, 3, 4, 5, 6 and 7 mol%. The results showed that the doping of Er2O3 ions with more concentration increased glass density, molar volume, and refractive index. Absorbed photons with 388 nm can excite the glass samples to release the strongest emission at 530 nm wavelength. The suitable concentration of adding Er3+ ions into La2O3-B2O3 glass showed strongest light emission at 5 mol% concentration of Er2O3. NIR luminescence spectra was studied under 978 nm excitation wavelength of Er3+ doped La2O3-B2O3 glass. NIR emission peak was centered at 1544 nm. The Judd-Ofelt (JO) Ωλ (λ = 2, 4, and 6) parameters were calculated to explore the nature of environment surrounding the Er3+ ions. Absorption and stimulated emission cross-sections have been evaluated by applying Mc Cumber theory, the resulting value is 8.25 × 10−21 cm2. This research is beneficial for use as a NIR laser media in solid state emitting wavelength at 1544 nm. The optical gain G(λ) properties have been derived from the σabs and σemi values that the gain is positive for 40% population inversion in the 1400-1700 nm wavelength range.

Spectroscopic Characterization and CIE Coordinate of Pr3+ Ions Doped Pottasium Aluminum Gadolinium Phosphate Glasses

Six samples of Pr3+ ions doped potassium aluminum gadolinium phosphate (KAGP) glasses were synthesized using the melt-quenching method. The values of density and refractive index of glasses tend to rise with the concentration of Pr2O3 due to increased interaction between the Pr3+ ions and non-bridging oxygen. Optical absorption spectra and luminescence have been investigated. Hypersensitive transitions were identified by the highest intensity of absorption spectra, which recorded at the wavelengths of 444 and 1527 nm corresponding transitions 3H4 → 3P2 and 3H4 → 3F3. The emission bands of Pr3+ ions in the visible bands were observed under the excitation 444 nm. Among them emission bands at 597 nm (1D2 → 3H4) showed highly intensity and concentration quenching of emission faster than those of 3P0 and 3P1 due to the cross-relaxation. The Commission International De I'Eclairage (CIE) 1931 chromaticity coordinates of KAGPPr4 glasses lie in yellowish-orange region to orange region. Based on the studies characteristics, Pr3+ 0.5 mol% doped KAGP glasses are suitable for guided as a great host that can emit yellowish-orange laser and suitable for optical device also.

High‐coordinated alumina and oxygen triclusters in modified aluminosilicate glasses

AbstractAluminosilicate glasses are ubiquitous in high‐performance displays due to their favorable thermal, mechanical, and optical properties. They also exhibit interesting structural features depending on the ratio of alumina to modifiers in the glass system. Excess modifiers exist in the metaluminous region, while the peraluminous region contains more negatively charged alumina structures than modifiers. As the composition switches from metaluminous to peraluminous, anomalous changes in properties such as the glass transition temperature, viscosity, and refractive index occur. This has been explained with two contrasting structural transformations to accommodate the lack of charge‐balancing modifiers: either aluminum increases in coordination (forming five‐coordinated or six‐coordinated Al) and/or oxygens become three‐coordinated (known as triclusters). The precise charge‐balancing mechanism remains a subject of much debate in the community. This review highlights this structural debate by providing a chronological understanding of how these two theories evolved. We also summarize the state‐of‐the‐art understanding of the aluminosilicate glass structure. By gaining a more comprehensive view of the two opposing structural views within the aluminosilicate glass system, we can gain insights on valuable future research from both experimental and modeling perspectives.

3D micro-structuring by CW direct laser writing on PbO-Bi2O3-Ga2O3 glass

Direct laser writing was successfully performed into high refractive-index glasses with the composition of (PbO)0.75-x(Bi2O3)x(Ga2O3)0.25for x = 0–0.3, using focused continuous-wave laser beam emitting at 447 nm. The local changes in the material dimensions were induced by the illumination. Due to local overheating of the illuminated area microlenses and microcraters were formed. The overheating magnitude was calculated employing COMSOL-SWfor illumination time 0.5 s and directly measured for the steady-state conditions.The microlens and microcrater formations with potential applications in optics were studied and the role of Bi2O3content on their formation was investigated. The glasses with different Bi2O3content had similar optical (penetration depth of laser), physical (density) and thermal (coefficient of thermal expansion) properties. On the contrary, the threshold power densities of the microlenses formationand microlines or their heights were significantly affected by the Bi2O3presence. No changes in the chemical compositionand structural arrangement were observed between non-illuminated materials and the objects (microlenses, microlines) formed by direct laser writing.However, the nanoindentation hardness of the objects was significantly lower compared to non-illuminated glass. The threshold power density of microcraters formationdoes not depend on the chemical composition due to the similar residual roughness of the surfaces.

Characterization of a Radiofluorogenic Polymer for Low-Energy Electron Beam Penetration Depth Visualization.

Low-energy (80–300 keV) electron beam accelerators are gaining in importance in the radiation processing industry due to their ease of use and wide range of applications (e.g. product surface sterilizations or polymer curing and cross-linking). Due to their very low penetration depth (tens to hundreds of microns), currently used film dosimeters exhibit dose gradients over their thickness and do not resolve the dose response in the first microns of the irradiated material. Hence, the surface dose, defined as the dose in the first micron Dµ, cannot be measured directly. This study presents a polymer material as a dosimeter candidate for high-dose low-energy electron beam irradiations. The readout of the dose-dependent fluorescence intensity, originating from a pararosaniline dye reaction when irradiated, is measured using fluorescence microscopy. So far, no in-depth characterization of the material has been performed, leaving the stability and fluorescence properties of the material not fully optimized. We describe the improvements in polymer composition and the fabrication method, and characterize the material properties in terms of the thermal stability, glass transition temperature, refractive index, hardness, rheological behavior, and water affinity. All of these create a complex set of requirements a polymer needs to fulfill to become an effective dosimeter when measuring using confocal microscopy. The fluorescence readout procedure will be addressed in further studies.

Study on the optical and thermal properties of a new mid-infrared TeO2-Ta2O5-La2O3 glass

A new mid-infrared tellurite ternary glass with small glass formation area was prepared by modified melt quenching. A high-throughput, simple and fast glass melting process is realized by erecting the tube furnace sideways. The forming range of glass can be quickly and efficiently explored. Moreover, the equipment is convenient for stirring in the melting process, and can effectively reduce bubbles and stripes in the molten glass, thus preparing the matrix glass with excellent performance. The maximum phonon energy of the glass is 765 cm−1, and the appropriate phonon energy is beneficial to achieve intense mid-infrared luminescence or laser. The density of glass is 5.385 g/cm3, indicating high refractive index of this new glass. The glass transition temperature is 428 °C, and there is no obvious crystallization thermal effect before the glass melts. The thermal expansion coefficient of TeO2-Ta2O5-La2O3 (TTL) glass is 12.5 × 10−6K−1 (25–300 °C). The refractive index of glass is 2.01 and the Abbe number is 21.48. The maximum transmittance in the near infrared range is between 76.44% and 80.85%, while the theoretical transmittance is 80.08% (2700 nm). Therefore, this glass is a promising laser glass matrix material in the 2.0–2.7 μm band.

Influence of extrusion on the properties of chalcogenide glasses and fibers

The influence of extrusion on the properties of chalcogenide glasses and fibers was investigated systematically via measuring and analyzing their structural and physical properties of Ge10As22Se68 and As2S3. The experimental results showed that the extrusion processing has an insignificant effect on the glass network, crystallization, and compositions, but does have an influence on the glass transmission rate, refractive index and density. Meanwhile, the fiber loss after extrusion processing was greatly improved with 57.65% or 71.43%, corresponding to Ge10As22Se68 or As2S3 fiber, respectively.

High-precision molding simulation prediction of glass lens profile for a new lanthanide optical glass

Precision glass lens molding (PGLM) is a recently developed method for fabricating glass optical components with high precision in large volumes. Lanthanum optical glasses are extensively used as optical materials owing to their superior optical properties, such as high refractive index, low dispersion, and high transparency. However, the transformation temperature of currently available high refractive index glass is generally above 650 °C and poses a challenge in manufacturing ultra-hard molds, durable coatings, and high-temperature molding equipment using PGLM. In this study, a preparation method for obtaining high refractive index, low -melting -point lanthanide optical glass (B-ZLaT198) used in PGLM was developed to reduce the transformation temperature. The developed method also characterizes the glass refractive indices and thermal-mechanical properties. To achieve the high-precision prediction of a molding shape in a simulation, a viscoelastic constitutive model of glass was established based on a micro-deformation uniaxial compression creep test. Moreover, by solving the Tool-Narayanasway-Moynihan model parameters based on the specific heat capacity fitting of optical glass at different heating and cooling rates, the input parameters of the structural relaxation model (SRM) for simulation prediction of aspheric glass lens profile deviation in the annealing stage were obtained. Finally, the profile deviation of the aspheric lens was predicted using a finite element model simulation. The results showed that the simulation’s predicted profile of an aspheric lens using the SRM model was in good agreement with that of experimental molding profile. In addition, using the SRM provided a higher prediction accuracy than that of the thermal expansion model in the annealing stage. Adopting the SRM was necessary for the annealing simulations of molding pressing and also verified the accuracy of the proposed viscoelastic characterization method for calculating the thermomechanical parameters of optical glasses.

The role of fluorine in high quantum yield oxyfluoride glasses and glass-ceramics

Oxyfluoride glass-ceramics is considered a great candidate for optical refrigeration. Their ability to form low-phonon fluoride crystals embedded in an oxide glass matrix presents great interest for the development of fluorescent efficient materials with good mechanical and thermal resistance. A better understanding of the material microstructure and its relations on properties is mandatory to achieve the required optical refrigeration values. In the present work, we discuss the effect of fluoride compound evaporations and their impacts on thermal, optical, crystallization, and luminescent properties. Using different melting temperatures, glass samples from the theoretical molar composition 37.6 SiO2 – 22.4 Al2O3 – 19 YF3 – 20 LiF – 1 YbF3 are fabricated by the melt-quenching method. The relation between composition and glass properties is assessed by measurement of glass transition, crystallization temperature, density, refractive index, and optical transmission. A detailed study of the crystallization behavior of the samples is conducted using scanning and transmission electron microscopies, and both classical and temperature in-situ x-ray diffractions. Finally, luminescent properties are measured, including quantum yield, and both steady-state and time-resolved spectroscopies.

Effect of Soaking Time and Sb2O3 Concentration on Number of Bubble and Optical Properties of Borosilicate Glasses

Borosilicate glasses were fabricated with antimony oxide (Sb2O3)-doped in the formula of SiO2-B2O3-Na2O-CaO-ZnO, by using the melt-quenching method at 1200 °C which various soaking time of 3, 4, 5, 6, and 7 h. The results show that the density, molar volume and refractive index of glasses increased with increasing of Sb2O3 concentration. However, the density of glasses decreases with increasing soaking time. The transmittance spectra present the absorption around 1050 nm and 450 nm which corresponds to Fe2+ ion and Fe3+ ion, respectively. This absorption strength decreases with increasing Sb2O3 concentration which shows the highest strength at 0.0 mol% of Sb2O3 content. Moreover, the decrease in the number of bubbles in the glass is dependent on the increase of the Sb2O3 concentration and soaking time.

Investigation Bi-Slag Glass Systems for Radiation Shielding

In this research, Bi-slag glass systems were prepared in the laboratory using the conventional melt quenching method at 1200 °C and were investigated for their radiation shielding properties at different photon energies from 80 to 1332 keV. 133Ba, 137Cs and 60Co sources have been used for experimental measurements. The mass attenuation coefficient of gamma-rays was compared with the one that was estimated theoretically by WinXCom computer software. The results showed that the experimental values of the mass attenuation coefficient (), effective atomic number (Z eff) and effective electron densities (N el) are in good agreement with theoretical values. Half value layer (HVL) and mean free path (mfp) of glass systems are also reported and compared with some standard shielding materials, and the results showed better radiation shielding compared to standard shielding materials. In addition, the absorption and refractive indices of glasses have been investigated and discussed.

Synthesis of Precisely Structured Olefin Copolymers by Phenylseleno Oxidation Elimination

AbstractSelenium‐containing polymers have attracted considerable attention due to their unique redox responsiveness. Here, phenyl vinyl selenide (PVSe), as a functional selenium‐containing monomer, is polymerized with maleimide (MI) or its derivatives by reversible addition–fragmentation chain transfer polymerization. The resulting polymers are characterized by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectroscopy and proton nuclear magnetic resonance spectra, which particularly prove the obtaining of alternating polymers through the polymerization of PVSe and MI or its derivatives. Properties of the resulting polymers are systematically investigated, such as glass transition temperature, thermal performance, and refractive indices. What's more, based on phenylseleno oxidation elimination, the alternating polymers are oxidized through 30% H2O2 to form precisely structured olefin copolymers with carboncarbon (CC) double bonds. The selective generation of double bonds in the alternating polymers is systematically studied. The efficiency of such oxidation is very high under mild conditions due to low electronegativity and bond energy of carbonselenium (CSe) bond, which provides a novel method to prepare precisely structured olefin copolymers with MI or its derivatives.

Numerical Modeling of Radiation Focusing by Dielectric Microcylinders with Several Layers

In this paper, the light focusing by dielectric microcylinders with several layers was numerically studied by using the finite element method implemented in COMSOL Multiphysics. Different materials for the top layer were proposed during the research (refractive indices are 1.59, 1.8, 1.9) while the core was proposed from fused silica glass (refractive index is 1.45). It was shown that the dielectric shell allows to increases the maximum intensity of the formed photonic nanojet. Choosing the design of a two-layered microcylinder it is possible to form a compact focal spot (TE-polarization) or increase the length of the produced photonic nanojet. Obtained results were verified by another software package FullWAVE which implements a finite difference time domain method. The simulation results are in good agreement.

Absolute multilateration-based coordinate measurement system using retroreflecting glass spheres

We have measured the three-dimensional coordinates of retroreflecting glass spheres using a multilateration technique. To this end, the distances between each target and our measurement heads have been determined by an in-house prototype of electro-optical absolute distance meter. The used targets are spheres of glass refractive index n = 2 and of diameter 14.2 mm. They offer a much larger aperture than corner cubes and a lower cost, but they present a low reflectivity. However, this paper shows that with a proper collimation of the laser beams it is possible to reach a range of operation of 20 m. The standard uncertainty on such distances is better than 11 μm, including the mechanical errors of the gimbal mechanisms of our aiming systems. This uncertainty has been validated thanks to a comparison with an interferometric bench. In addition, the measurement of the coordinates of 16 glass spheres using a self-calibration multilateration algorithm has also confirmed the performances of the developed system: the standard deviation on the position errors has been estimated to about 10 μm.

Measurement of glass thickness and refractive index based on spectral interference technology.

A non-contact glass thickness and refractive index measurement method based on spectral interferometry is proposed. The method uses the Michelson interference principle to calculate the interference signal obtained by the spectrometer using the Fourier transform algorithm to obtain the modulation period of the spectral interference fringes. The geometrical thickness and refractive index of a glass sample can be calculated from the optical path difference between the reflected light of the reference arm and that of the front and back surfaces of the glass sample before and after being placed in the measuring arm. The linear interpolation method is used to resample the interference pattern in the frequency domain to ensure uniform sampling. It also adopts an improved phase extraction algorithm in the Fourier domain, which improves the anti-interference ability of the measurement system, and it exhibits a fast detection speed and high signal-to-noise ratio. To verify the accuracy of the measurement results of this method, a high-precision coordinate measuring machine is used for comparative experiments, and the characteristics of the tested object are analyzed. The experimental results show that the measurement accuracy of the system is in good agreement with that of a high-precision coordinate measuring machine.

Study of ferroelectric nanocomposites based on P(VDF-TrFE) by scanning probe microscopy

Ceramic and polymer based nanocomponents combine the properties of their constituents, e.g. flexibility, elasticity, polymer reprocessability, hardness typical of glass, wear resistance and high light refraction index. This helps improving many properties of the materials in comparison with the source components. Since recently researchers have been manifesting interest to the properties of complex composite compounds. This is primarily caused by the unique properties of their structures as compared with conventional materials having homogeneous composition. Secondly, this interest is caused by the fact that these compounds may prove to be much cheaper than homogeneous structures provided the physical properties of the composite in a preset range of parameters (temperature, applied field frequency etc.) are identical to those of the respective homogeneous materials. For example, polyvinyl idenfluoride (PVDF) type ferroelectric polymers and copolymers on its basis have found wide application for functional elements of various electromechanic devices in advanced electronics due to their relatively good piezoelectric and pyroelectric properties. The strong random polarization and the formation of polar non-centrosymmetric crystals provide for the high piezoelectric and pyroelectric activity in these crystals. Scanning probe microscopy has been used for study of ferroelectric nanocomposites having different compositions. The matrix specimen for study of local polarization switching at a nanoscale level was vinyl idenfluoride and trifluoroethylene P(VDF-TrFE) copolymer possessing sufficiently high crystallinity. The composite fillers were barium titanate BaTiO 3 and deuterized triglycinsulfate DTGS ferroelectric powders and zirconate-titanate lead barium BPZT ceramic powder. We show these materials to show good promise for use in memory cells.

Bayesian mixture modelling for glass refractive index measurement

Glass is a common type of physical evidence in forensic science. Broken glass recovered from a suspect may have similar physical characteristics to glass collected at a crime scene and therefore can be used as evidence. Statistical treatment of this evidence involves computing a measure of the weight of evidence. This may be done in a Bayesian framework that incorporates information from the circumstances of the crime. One of the most crucial quantities in this calculation is the assessment of the relative rarity of the characteristics of the glass, essentially the probability distribution used to model the physical characteristics of recovered glass. Typical characteristics used in casework are the elemental composition of glass and the refractive index measurement. There is a considerable body of scientific literature devoted to the modelling of this information. For example a kernel density estimation has been used to model the background population of glass based on the refractive index measurement and a multivariate Gaussian finite mixture model has been used to model the elemental composition of glass. In this paper, we present an alternative approach, the Dirichlet Process Mixture Model, to model the glass refractive index measurement in a Bayesian methodology. A key advantage is that using this method allows us to model the probability density distribution of refractive index measurements in a more flexible way.

Scanning probe microscopic study of P(VDF-TrFE) based ferroelectric nanocomposites

Ceramic and polymer based nanocomponents combine the properties of their constituents, e.g. flexibility, elasticity, polymer reprocessability, hardness typical of glass, wear resistance and high light refraction index. This helps improving many properties of the materials in comparison with the source components. Since recently researchers have been manifesting interest to the properties of complex composite compounds. This is primarily caused by the unique properties of their structures as compared with conventional materials having homogeneous composition. Secondly, this interest is caused by the fact that these compounds may prove to be much cheaper than homogeneous structures provided the physical properties of the composite in a preset range of parameters (temperature, applied field frequency etc.) are identical to those of the respective homogeneous materials. For example, polyvinyl idenfluoride (PVDF) type ferroelectric polymers and copolymers on its basis have found wide application for functional elements of various electromechanic devices in advanced electronics due to their relatively good piezoelectric and pyroelectric properties. The strong random polarization and the formation of polar non-centrosymmetric crystals provide for the high piezoelectric and pyroelectric activity in these crystals. Scanning probe microscopy has been used for study of ferroelectric nanocomposites having different compositions. The matrix specimen for study of local polarization switching at a nanoscale level was vinyl idenfluoride and trifluoroethylene P(VDF-TrFE) copolymer possessing sufficiently high crystallinity. The composite fillers were barium titanate BaTiO3 and deuterized triglycinsulfate DTGS ferroelectric powders and zirconate-titanate lead barium BPZT ceramic powder. We show these materials to show good promise for use in memory cells.

Radiation shielding competencies for waste soda–lime–silicate glass reinforced with Ta2O5: experimental, computational, and simulation studies

In this study, the authors emphasized an incisive purpose as the valorization of waste soda–lime–silicate glass (SLS) for a potential gamma-rays shielding material. For this, xTa2O5-(100-x)SLS glass systems where x: 0, 0.005, 0.05, and 0.5 wt% were fabricated via conventional melting technique. The synthesized four glass specimens (RG and RGT1 to RGT3) were then subjected to physical, optical, and radiation shielding measurements. Simulation studies (MCNP-5) and theoretical computations (XCOM) were conducted to validate the findings. The results clearly showed that the insertion of Ta2O5 improved both physical and optical properties. In particular, RGT3, having a higher amount, possessed the highest glass density (ρglass) and refractive index (n) values. On the other hand, the transmission factor (TF) data revealed that increasing the thickness of the glass sample caused a notable decrease in the TF values. RG decreases from 92.233% to 78.461%, 61.562%, and 48.302% for thicknesses of 0.5 cm, 1.5 cm, 3 cm, and 4.5 cm. RGT3 shows the best radiation shielding potential out of the investigated waste SLS samples according to the several radiation shielding factors.