Laser-induced local change in optical properties of alkaline-borosilicate glasses

The process of the formation of microregions (MRs) in the volume of alkaline-borosilicate glasses using the method which includes the production of porous glass (PG) by leaching two-phase alkaline-borosilicate glass in acid and the action on PG of laser radiation of a wavelength practically not absorbed by glass has been studied. The optical properties of MRs and the possibility of their preservation after PG sintering in a furnace to obtain a quartzoid glass are studied.     

Sol-gel preparation and optical properties of transparent sodium borosilicate glasses

The emission spectra were measured for the sol-gel glass 5.7Na₂O · 19B₂O₃ · 75.35SiO₂ with chemical composition prepared under different experimental conditions, and the characteristic features of emission spectra are discussed. The results show the broad visible (500–750 nm) and IR (850–1350 nm) emission with unique light-emitting properties were found in NBS solgel glass.     

Structural, optical and bioactive properties of calcium borosilicate glasses

Glass of composition 40SiO₂–20B₂O₃–30CaO–10M₂O₃ (M = Al, Cr, Y and La) were prepared by the splat quenching technique to investigate the effect of M₂O₃ on their bioactivity, structural and optical properties. Y₂O₃ and Cr₂O₃ containing glasses formed a crystalline hydroxyapatite (HA) layer after dipping in simulating body fluid (SBF) for 25 days. On the other hand, HA layer could not form in Al₂O₃ and La₂O₃ glasses. However, during soaking in SBF solution, these glasses exhibit higher dissolution rate, lower density and increased optical band gap as compared to unsoaked glasses. Their oxygen molar volume was also higher than for Y₂O₃ and Cr₂O₃ glasses. The change in composition affects the cross-link formation in the glass matrix and finally its durability and bioactivity in SBF. The results show that M₂O₃ plays an important role in controlling chemical durability and bioactivity of the glasses.     

Enhanced nonlinear optical and optical limiting properties of graphene/ZnO hybrid organic glasses

Graphene/ZnO (G/ZnO) composites were synthesized for the first time by a wet chemical method. X-ray diffraction and transmission electron microscopy analyses demonstrated that ZnO nanoparticles with an average diameter of about 5 nm uniformly covered the graphene surfaces. G/ZnO composites were dispersed in methyl methacrylate (MMA), polymerized at 75 °C for 30–35 min, and finally, dried at 45 °C for 10 h, to afford G/ZnO/PMMA organic glasses. UV–visible spectra showed that the band gaps of the G/ZnO/PMMA organic glasses were about 3.54 eV, larger than that of bulk ZnO because of the small size effect of ZnO nanoparticles. The nonlinear optical (NLO) and optical limiting (OL) properties of the G/ZnO/PMMA organic glasses were investigated by a modified Z-scan technique. The total NLO coefficient α₂ of the G/ZnO/PMMA organic glass was as high as 1530 cm/GW, which was approximately 5.6 and 7.8 times larger than those of G/PMMA and ZnO/PMMA organic glasses. The enhanced NLO properties of the G/ZnO/PMMA organic glasses led to excellent OL performance, which was attributed to the positive synergistic effects between graphene and ZnO.     

Interpreting the optical properties of oxide glasses with machine learning and Shapely additive explanations

Due to their excellent optical properties, glasses are used for various applications ranging from smartphone screens to telescopes. Developing compositions with tailored Abbe number (V_d) and refractive index at 587.6 nm (n_d), two crucial optical properties, is a major challenge. To this extent, machine learning (ML) approaches have been successfully used to develop composition–property models. However, these models are essentially black boxes in nature and suffer from the lack of interpretability. In this paper, we demonstrate the use of ML models to predict the composition-dependent variations of V_d and n_d. Further, using Shapely additive explanations (SHAP), we interpret the ML models to identify the contribution of each of the input components toward target prediction. We observe that glass formers such as SiO₂, B₂O₃, and P₂O₅ and intermediates such as TiO₂, PbO, and Bi₂O₃ play a significant role in controlling the optical properties. Interestingly, components contributing toward increasing the n_d are found to decrease the V_d and vice versa. Finally, we develop the Abbe diagram, using the ML models, allowing accelerated discovery of new glasses for optical properties beyond the experimental pareto front. Overall, employing explainable ML, we predict and interpret the compositional control on the optical properties of oxide glasses.     

Synthesis of silicon carbonitride dielectric films with improved optical and mechanical properties from tetramethyldisilazane

Films of silicon carbonitride have been obtained by the plasma chemical decomposition of a gaseous mixture of helium and a volatile organic silicon compound 1,1,3,3-tetramethyldisilazane (TMDS) in the temperature range of 373–973 K. The modeling of the processes of deposition from a gaseous mixture (TMDS + He) in the temperature range of 300–1300 K and pressures of P _total ⁰ = 10^?2–10 Torr has shown that it is possible to vary the equilibrium composition of the condensed phase depending on the synthesis temperature and the initial gaseous mixture composition. The chemical and phase compositions, as well as physicochemical and functional properties, of the films obtained in the range of 373–973 K have been studied using a complex of modern techniques, including Fourier transformed infrared (FTIR) Raman, X-ray photoelectron (XPS) and energy-dispersive spectroscopy (EDS), scanning electron (SEM) and atomic-force microscopy (AFM), X-ray diffraction using synchrotron radiation (XRD-SR), ellipsometry, and spectrophotometry. The electrophysical parameters are determined using the C-V and I-V characteristics, and the microhardness and Young’s modulus are determined by the nanoindentation method. It is established that the chemical composition of low-temperature (373–673 K) films of silicon carbonitride corresponds to a gross formula of SiC _x N _y O _z : H, while that of high-temperature films corresponds to SiC _x N _y . The presence of nanocrystals with the phase composition close to the standard phase α-Si₃N₄ is detected in the films. It is shown that all of the films are perfect dielectrics (k = 3.8–6.4, ρ = 2.2 × 10¹⁰?1.3 × 10¹¹ Ohm · cm), possess high transparency (～98%) in a wide spectral range of 280–2500 nm, and have a high microhardness (3.8–36 GPa) and Young’s momentum (125–190 GPa).     

Newly developed BGO glasses: Synthesis,optical and nuclear radiation shielding properties

In this research paper, we studied the optical and nuclear shielding efficiency of newly developed BGO glasses with the following compositions (in wt%): 32Bi₂O₃–68GeO₂, 42Bi₂O₃–58GeO₂, 47Bi₂O₃–53GeO₂, 52Bi₂O–48GeO₂, 62Bi₂O₃–38GeO₂. BGO glasses were prepared by traditional melt quenching method. To obtain the band gap values of fabricated BGO glasses, optical absorption spectra were used for evaluation of optical properties. The mass attenuation coefficients (μ/ρ) were achieved for prepared glasses at 0.015–15 MeV photon energies employing MCNPX Monte Carlo code and WinXcom program. Moreover, broad-range of nuclear shielding parameters for gamma ray, neutrons and charged particles such as mass attenuation coefficient, half value layer, effective atomic number, buildup factors, mass stopping powers, projected ranges, fast neutron removal cross sections and damage factors were calculated. The refractive index is calculated from E_opt, As Bi₂O₃ concentration is enhanced, E_opt is also increased as well as the optical electronegativity and consequently the refractive index. In addition, the results showed that BIGE5 glass sample with highest Bi₂O₃ contribution has excellent nuclear radiation shielding ability among the other fabricated glass samples.     

Influence of molybdenum oxide on structural,optical and physical properties of oxychloride glasses for nonlinear optical devices

The unconventional Heavy Metal Oxide Glasses (HMOG) are characterized by a low phonon energy, large infrared range transmission, high refractive index and nonlinear optical properties. Ternary glasses have been synthesized and studied in the Sb₂O₃– MoO₃-ZnCl₂ system. Further, the glass formation compositional limits are reported and some glass samples with the formula: (90-x)Sb₂O₃ -xMoO₃–10 ZnCl₂ (10 ≤ x ≤ 50, mole%) were elaborated. Thermal properties have been measured and indicating that the glass transition temperature decreases with increasing proportions of molybdenum oxide. The evolution of density, microhardness and elastic modulus has been studied as functions of parameter x and Raman spectra measurements have been shown the partial conversion of MoO₆ octahedral units into MoO₄ tetrahedral.     

Cation-substitution induced stable GGAG:Ce3+ ceramics with improved optical and scintillation properties

Among the aluminate garnet materials, cerium doped gadolinium gallium aluminum garnet ceramics (GGAG:Ce) have shown great performance advantages, which suggests their promising applications in medical imaging, high energy rays detection and high power LED lighting. The goal of this work is to raise the thermostability of GGAG:Ce by means of partial Y³⁺ substitution, and to find out the relationship between the crystal structure and the optical properties. GGAG:Ce³⁺,xY³⁺ ceramics were prepared via chemical precipitation, and a combination of sintering in oxygen atmosphere and hot isostatic pressing. In order to identify the detailed crystal structure information, Rietveld refinements were first taken on the XRD patterns. Crystal structure refinements verify the ability of mutual substitution of Y and Ga atoms between the dodecahedron and octahedral sites. The optical, luminescent and scintillation properties have been investigated. Results show that the transmittance of the sample can reach 77% at the emission peak wavelength, while the spectrally corrected light yield value reaches 61,000 ± 1200 photons/MeV.     

Quantitatively predicting the optical and spectroscopic properties of Nd3+-doped laser glasses

Predicting the properties of glass based on compositional and structural information is a fundamental issue with enormous practical and industrial significance for the study of laser glass. Here we address this problem and demonstrate the application of phase diagram method in predicting the spectroscopic properties of Nd³⁺-doped binary and ternary silicate, binary phosphate, and borate laser glasses from their initial congruently melting compounds. In particular, spectroscopic properties, such as effective linewidth (Δλ_eff) and fluorescence branching ratio (β) can be precisely predicted in all glass systems with an error less than 5%. Furthermore, a composition–structure–property database of Nd³⁺-doped ternary silicate glass system is established and preliminarily applied to the composition design and explanation of commercial glass. This study provides interpretable predictions of the optical and spectroscopic properties for Nd³⁺-doped laser glasses.     

Melting optical glasses in high-frequency furnaces

Translated from Steklo i Keramika, No. 5, pp. 11–13, May, 1988.     

New inorganic glasses for optical waveguides

Recent advances in lightwave technology, including optical fibres, optical amplifiers, optical couplers and a variety of non-linear optical effects and devices, have created the need for a new range of glass materials. These glasses may themselves have properties tailored for the application or may play the role of host for an active guest species. In this review, the types of glass systems currently being developed will be reviewed with a focus on the different properties offered by different chemical makeup. Specific examples will include recent work on Heavy Metal Fluorides and Heavy Metal Oxides.     

Structural,thermal, dielectric and ac conductivity properties of lithium fluoro-borate optical glasses

Transparent and stable glasses in the chemical composition of Li₂O–LiF–B₂O₃–MO (M = Zn and Cd) have been prepared by a conventional melt quenching method. For these glasses, absorption spectra, structural (XRD, FT-IR, and Raman spectra), thermal (TG–DTA and DSC), dielectric (?′, ?″, tan δ), ac conductivity (σ_ac), and electric modulus (M′ and M″) have been investigated. Amorphous nature of these glasses has been confirmed from their XRD profiles. The LFB glasses with the presence of ZnO or CdO an extended UV-transmission ability has been achieved. The measured FT-IR and Raman spectra have exhibited the vibrational bands of B–O from [BO₃] and [BO₄] units and Li–O. The dielectric properties (tan δ, dielectric constant (?′), dielectric loss (?″)), electrical modulus and electrical conductivity (σ_ac) of these glasses have also been studied from 100 Hz to 1 MHz at the room temperature. Based on the trends noticed in the ac conductivities, the present glasses could be found useful as battery cathode materials.     

Physical properties of (100-x) B2O3 xLiF optical glasses

This short note brings out the physical properties of the lithium borate glasses of the composition : (100-x)B₂O₃ + xLiF [where x = 2.5, 5, 10, 20, 30 and 40 in mol %] as the function of Li⁺ ion concentration.