Glass Interface Research Articles

Underwater Refractive Stereo Vision Measurement and Simulation Imaging Model Based on Optical Path

When light passes through air–glass and glass–water interfaces, refraction occurs, which affects the accuracy of stereo vision three-dimensional measurements of underwater targets. To eliminate the impact of refraction, we developed a refractive stereo vision measurement model based on light propagation paths, utilizing the normalized coordinate of the underwater target. This model is rigorous in theory, and easy to understand and apply. Additionally, we established an underwater simulation imaging model based on the principle that light travels the shortest time between two points. Simulation experiments conducted using this imaging model verified the performance of the underwater stereo vision measurement model. The results demonstrate that the accuracy achieved by the new measurement model is comparable to that of the stereo vision measurement model in the air and significantly higher than that of the existing refractive measurement model. This is because the light rays from the camera’s optical center to the refraction point at the air–glass interface do not always intersect. The experiments also indicate that the deviation in the refractive index of water lead to corresponding systematic errors in the measurement results. Therefore, in real underwater measurements, it is crucial to carefully calibrate the refractive index of water and maintain the validity of the calibration results.

Protein assay and immunoassay based on nematic thermotropic and lyotropic liquid crystals quantitated by haze measurement

Haze measurement is the cornerstone for assessing the transparency or opaqueness of liquid crystals (LCs) in applications such as smart windows and display technologies. In this study, we present a novel application of haze measurement as the quantitative approach for LC-based biosensing. Protein assay with bovine serum albumin (BSA) as the protein standard and immunoassay of the cancer biomarker CA125 were performed with the thermotropic LC 5CB and the nematic phase of the lyotropic chromonic LC sunset yellow. We observed that the brightness of LC optical texture increased with increasing analyte concentration due to enhanced light leakage caused by the attenuation of the vertical anchoring force of the surface alignment reagent coated on the glass surface. On the other hand, the haze value decreased as the amount of BSA or CA125 at the LC–glass interface increased, indicating that the scattering angle of the incident light was reduced. By calculating the percent difference in haze value, W (%), which gave rise to a positive correlation between the result of haze analysis and analyte concentration, a limit of detection (LOD) of 1.2 × 10−3 and 5.6 × 10−5 g/mL for BSA and CA125, respectively, was achieved by detection with 5CB, whereas the LOD values for BSA and CA125 were 1.0 × 10−12 and 1.9 × 10−9 g/mL, respectively, when detected with nematic sunset yellow. To the best of our knowledge, this study provides the first demonstration of the feasibility and simplicity of quantitative analysis by haze measurement in LC-based biosensing.

Three-dimensional object reconstruction based on spin–orbit interaction of light

Three-dimensional (3D) reconstruction has received extensive attention in recent years and is of great significance to various application fields. We propose a simple method of 3D object reconstruction based on spin–orbit interactions occurring from light reflection at the air–glass interface. By rotating the object, edge images of the object in various orientations are obtained; we overlap these edge images to ultimately reconstruct the 3D object. This 3D image detection based on spin–orbit interaction of light provides a low energy consumption, low cost, and more algorithmic method compared to traditional 3D image processing. This can be used in fields such as medicine, autonomous vehicles, planetary observation, and other areas.

Goos–Hänchen shifts on spin representation

We analyze the Goos–Hänchen (GH) shift and longitudinal spin splitting (LSS) at a planar interface between two optical media in the spin representation. While these optical effects have been studied previously, we examine the direct and cross-reflected light fields, and their interference from the spin representation to reveal the physical mechanism of the GH shift and establish a quantitative relationship between it and LSS. Furthermore, we show that angular asymmetric spin splitting occurs under the spin representation when linearly polarized light with a phase difference of 180° and an amplitude ratio angle deviating from 45° impinges on the air–glass interface at Brewster’s angle. Finally, we reveal that the spin component field of the reflected light field for the total reflection case is different from that of the Brewster angle reflection, the most typical manifestation is that the intensity of the two spin component fields is not equal.

Measurement of the interfacial energy release rate (ERR) and cohesive law parameters of polyvinyl butyral laminated glass using a novel beam-type test specimen

The polyvinyl butyral (PVB) laminated glass (LG) structures are widely used in architectural and automotive sectors. Determination of the interfacial fracture energy (i.e. G) between the PVB layer and glass is one of the most vital procedures for ensuring the structural safety and fracture resistance of these kinds of components. The present study investigates the adhesion characteristics between glass and PVB interface in a LG composite structure. A new simple test fixture is introduced to measure the mixed-mode fracture energy from pure mode I (i.e. GI) to pure mode II (i.e. GII). By making use of the concept of Equivalent material Concept (EMC), linear elastic fracture mechanics (LEFM) formulations together with finite element (FE) analysis can be used to compute the compliance parameter of the system and pure modes I/II fracture energies. Besides, the interaction of cohesive forces between the PVB layer and glass are simulated by using a FE method based on a bi-linear cohesive zone model (CZM) technique. In this regard, the cohesive law parameters are computed for mode I and mode II in an iterative process. Then, the obtained pure mode cohesive law parameters are utilized to predict the mixed-mode load–displacement diagrams. The obtained results demonstrate the satisfactory accuracy of the cohesive law parameters and fracture energies in predicting the mixed-mode loading results across four different loading rates (i.e. LR = 2, 5, 10, and 15 mm/min).

Weak measurement of the Goos–Hänchen shift for a Hermite–Gaussian laser beam

We report on an experimental investigation of the Goos–Hänchen (GH) optical beam shift in the vicinity of the critical angle of incidence at an air–glass interface using a weak value amplification (WVA) technique for two mutually orthogonal first order Hermite–Gaussian (HG) modes (HG10 and HG01) of a light beam at 633 nm generated by a phase-only reflective spatial light modulator. We have developed a mathematical approach to visualize the beam shaping due to the WVA scheme of beam shifts for the HG modes. The study reveals the angle of incidence dependency of the GH shift in the total internal reflection condition. For both modes, a detailed study of the horizontal and transverse beam shift values with varied post-selection angles is also reported. In addition, a comparison of the beam shift values for both of the selected modes with the fundamental mode (HG00) has been demonstrated. We found a significant enhancement (about two to three times) in the beam shifts for the first order HG10 and HG01 modes compared to the fundamental mode (HG00). Our results clearly demonstrate the advantages of the HG modes of the light beam-exploiting WVA technique and thus may contribute significantly to this field and open up important applications in photonic manipulation and future technologies.

Molecular Interactions between Ionic Liquid Lubricants and Silica Surfaces: An MD Simulation Study.

The unique physicochemical properties of ionic liquids (ILs) attracted interest in their application as lubricants of micro/nano-electromechanical systems. This work evaluates the feasibility of using the protic ionic liquids [4-picH][HSO4], [4-picH][CH3SO3], [MIMH][HSO4], and [MIMH][CH3SO3] and the aprotic ILs [C6mim][HSO4] and [C6mim][CH3SO3] as additives to model lubricant poly(ethylene glycol) (PEG200) to lubricate silicon surfaces. Additives based on the cation [4-picH]+ exhibited the best tribological performance, with the optimal value for 2% [4-picH][HSO4] in PEG200 (w/w). Molecular dynamics (MD) simulations of the first stages of adsorption of the ILs at the glass surface were performed to portray the molecular behavior of the ILs added to PEG200 and their interaction with the silica substrate. For the pure ILs at the solid substrates, the MD results indicated that weak specific interactions of the cation with the glass interface are lost to accommodate the larger anion in the first contact layer. For the PEG200 + 2% [4-picH][HSO4] system, the formation of a more compact protective film adsorbed at the glass surface is revealed by a larger trans population of the dihedral angle -O(R)-C-C-O(R)- in PEG200, in comparison to the same distribution for the pure model lubricant. Our findings suggest that the enhanced lubrication performance of PEG200 with [4-picH][HSO4] arises from synergistic interactions between the protic IL and PEG200 at the adsorbed layer.

Effect of lead-free glass on the current transmission method at the Ag/Si interface in crystalline silicon solar cells.

Environmental protection mandates have spurred the widespread adoption of lead-free glass in electronic material adhesion. Glass powder, crucial for solar silver paste, notably affects the ohmic contact at the Ag-Si interface of crystalline silicon solar cells. This study examines how TeO2 content influences the high-temperature flowability and wettability of lead-free Bi2O3-TeO2-based glass powder, alongside the interplay between the glass's thermal properties and interface contact. Additionally, it investigates the Bi2O3-TeO2 ratio's impact on current transmission through the interfacial glass layer. Experimental results show that the synthesized glass powder exhibits superior high-temperature flowability and wettability, with a low contact resistance of 1.5 mΩ cm2 in silver paste applications. This study also proposes an optimal approach for enhancing current transmission through the interfacial glass layer. Consequently, this glass powder is highly valuable for c-Si solar cell silver paste applications, offering novel insights into improving current transmission efficiency.

Dissolution of simulated nuclear waste glass at high surface area to solution volume, high pH and 70 °C: comparison of international simple glass and SON68 glass.

Long-term static dissolution experiments, lasting up to ∼1500 days, were conducted on International Simple Glass (ISG) and SON68 glass under hyperalkaline pH, at 70 °C, and at a very high glass surface area to solution volume ratio. The study compared (1) glass dissolution kinetics, (2) secondary phase formation, and (3) the microstructure of the altered glass and secondary phase interface. Boron release indicated rapid initial dissolution followed by a slowdown mainly due to a significant pH drop. ISG reached a residual rate regime, while SON68 approached this regime near the experiment's end, with both glasses having similar final dissolution rates. Electron microscopy (SEM, TEM, EDS) of the reacted glass surfaces and the alteration products revealed nontronite formation on SON68, while C(A)SH phases and later rhodesite appeared on ISG, in addition to phillipsite-type zeolite formation observed in both experimental series. TEM observations revealed a porous, foam-like surface altered layer (SAL) near the pristine glass. SON68's SAL nanostructure, more complex than ISG's, had two porous zones, hindering water transfer and glass constituent release, in addition to a pH drop reducing silica network hydrolysis. TEM-EDS showed cation exchange and iron depletion in SON68's SAL, leading to nontronite formation. Secondary phases at the SAL-solution interface did not destabilize the SAL, and no alteration resumption was observed due to the pH drop below the threshold necessary for an alteration resumption due to zeolite formation. In conclusion, the combination of alkaline conditions and very high reaction progress does not lead to the dissolution of the glass by a dissolution-reprecipitation mechanism, as typically observed at much lower SA/V ratios. At the relatively mildly alkaline pH reached within the first year of the experiments, the diffusion of cations through the SAL becomes rate-controlling.

Picosecond Laser-Induced Bump Formation on Coated Glass for Smart Window Manufacturing

We report a study on the process of the formation of bubble-like structures on a coated glass surface using 50 ps laser pulses. The high-intensity interaction of laser radiation on the film–glass interface allowed us to develop a process for efficient glass bump formation. The high peak energy of the picosecond pulses has allowed us to merge the processes of coating evaporation and bubble growth into one. A parameter window was established within which efficient bump formation can be achieved. Well-defined spherical structures with a height up to 60 μm and a diameter up to 250 μm were obtained at pulse energy Epulse = 2.5 ÷ 4 μJ and laser fluence F = 2.5–0.41 J/cm2). The key aspects of the bump formation process were studied and are explained.

Diffusion zone evolution around growing crystals in combeite glass

AbstractThe precipitation of nonstoichiometric crystals (of different composition from the parent glass) motivated us to study the stoichiometric Na2O·2CaO·3SiO2 ( N2CS3) glass‐forming system comprehensively. The concentration profiles of Na and Ca in the diffusion zone around Na4+2xCa4−x[Si6O18], , crystals in an N2C3S glass were characterized by energy‐dispersive spectroscopy and were then theoretically described. We show that the diffusion zone is formed because of the rejection of part of calcium by the growing crystal. The radial variation of the Ca concentrations and the crystal nucleation rate through the diffusion zone were analyzed simultaneously. We found that the nucleation rate in the diffusion zone near the crystal–glass interface drastically decreases due to the increase in the work of critical cluster formation resulting from the composition change. In contrast, the diffusion activation barrier remains practically constant. Moreover, the Ca diffusion coefficients, DCa, in Na2O·2CaO·3SiO2 and CaO·SiO2 glasses show the same Arrhenius dependence, demonstrating that (surprisingly) DCa does not depend on the glass composition in the CaO·SiO2–Na2O·SiO2 metasilicate joint. This work provides the quantitative spatial distribution of chemical components in a partially crystallized glass, shedding light on solid solution crystallization in a glass‐forming liquid and its consequences.

Moisture and Glass Transition Temperature Kinetics of Ambient-Cured Carbon/Epoxy Composites

Carbon fiber reinforced polymer composites are widely used in the rehabilitation, repair, and strengthening of civil, marine, and naval infrastructure and structural systems. In these applications, they are exposed to a range of exposure conditions, including humidity and immersion, which are known to affect the durability of the resin and the fiber–matrix interface over long periods of time. This paper presents results of long-term hygrothermal aging of wet layup carbon/epoxy composites including through acceleration by temperature focusing on the development of a comprehensive understanding of moisture uptake kinetics and its effects on glass transition temperature and interface and inter-/intra-laminar dominated performance characteristics. A two-phase model for uptake that incorporates both diffusion- and relaxation-/deterioration-dominated regimes, as well as a transition regime, is shown to describe uptake well. The inclusion of damage terms to the diffusion and relaxation coefficients is seen to capture changes well, with the effective diffusion and relaxation coefficients increasing with fiber volume fraction and temperature. Effects of uptake, including at elevated temperatures, reflective of accelerated aging, on glass transition temperature and flexural strength are correlated, emphasizing a three-stage progression of overall response in line with the moisture uptake changes. The drop in glass transition temperature per percent increase in moisture uptake was seen to range from a low of 4.38% per % increase in moisture content, for the highest volume fraction at the highest temperature, to a high of 6.95% per % increase in moisture content, for the intermediate volume fraction at the lowest temperature. The composites with heavier fabric showed the greatest drop in both glass transition temperature and flexural strength, indicating a level of correlation between these characteristics as well. It is shown that both glass transition temperature and flexural strength show steep initial decreases, followed by a regime with slower decrease and, then, an asymptotic or near-asymptotic response with time of immersion, suggesting a close correlation with moisture uptake, which forms the basis for future modeling.

Cladding waveguide fabrication by femtosecond laser in Yb-doped phosphate glasses

Cladding waveguides near sample surface were investigated in Yb-doped phosphate glass using a femtosecond laser. The propagation of LP11-mode and dark-hollow beam was achieved using the circular cladding waveguides by adjusting the pulse energy and diameter of the cladding structure without inducing any damage tracks to the guiding core. Furthermore, semi-circular cladding waveguides with large-area and uniform-intensity modes were fabricated just below the glass surface. The working mechanism of the surface waveguide was clarified by analyzing the influence of the writing depth, which involves an overlapping between the mode at the upper end of the damage line and the mode adjacent to the glass interface. Finally, we successfully operated a 1030 nm laser by pumping the surface cladding waveguide at 976 nm.

Destruction of a magnesium alloy film in the condensed state by an ultrashort laser-driven shock wave

Laser-driven shock wave phenomena in a sub-micrometer Mg–4Al–2Zn alloy film are studied using spectral interferometry with spatial and temporal (1 ps) resolution. Upon irradiating the film through a glass substrate by 500 fs laser pulses, the ultrashort elastic compression pulses with the peak stress up to 4.6 GPa at a propagation distance of 0.5 μm were generated. Depending on the laser fluence, either spall fracture near the rear surface in the solid state or cavitation near the metal–glass interface in the liquid state was observed. The spall strength of the solid Mg alloy and the upper limit of the cavitation threshold in the melt at the strain rate of ∼109 s−1 were extracted from the free surface velocity history. The depth of fracture initiation was retrieved from the instant of the spall pulse exit, and the thickness of the molten layer was estimated to be 100–160 nm depending on laser fluence. The investigation of the residual morphology by scanning electron and atomic force microscopies revealed the presence of melting and nucleation within the irradiated area. The experimental findings are of interest for predicting the behavior of magnesium alloys in the condensed state at extremely high strain rates, for studying the physics of metastable states and for simulating the interaction of ultrashort laser pulses with thin film materials.

Atomistic simulations of calcium aluminosilicate interfaced with liquid water.

The dissolution behavior of calcium aluminosilicate based glass fibers, such as stone wool fibers, is an important consideration in mineral wool applications for both the longevity of the mineral wool products in humid environments and limiting the health impacts of released and inhaled fibers from the mineral wool product. Balancing these factors requires a molecular-level understanding of calcium aluminosilicate glass dissolution mechanisms, details that are challenging to resolve with experiment alone. Molecular dynamics simulations are a powerful tool capable of providing complementary atomistic insights regarding dissolution; however, they require force fields capable of describing not-only the calcium aluminosilicate surface structure but also the interactions relevant to dissolution phenomena. Here, a new force field capable of describing amorphous calcium aluminosilicate surfaces interfaced with liquid water is developed by fitting parameters to experimental and first principles simulation data of the relevant oxide-water interfaces, including abinitio molecular dynamics simulations performed for this work for the wüstite and periclase interfaces. Simulations of a calcium aluminosilicate surface interfaced with liquid water were used to test this new force field, suggesting moderate ingress of water into the porous glass interface. This design of the force field opens a new avenue for the further study of calcium and network-modifier dissolution phenomena in calcium aluminosilicate glasses and stone wool fibers at liquid water interfaces.

Effect of surface grain structure on reaction of residual glass phase with hydrofluoric acid in glass-ceramics

The rapid reactivity of hydrofluoric acid (HF) and irregular Si-O network has been successfully applied in the chemical processing of glass/glass-ceramics surface. It is found that the low glass and diopside (D-G) interface binding energy will promote the reaction of HF and the residual glass phase at the interface, resulting in the formation of defects and the fall of grain. Raman spectroscopy has found that residual stress will be generated on the surface of the sample during corrosion, which will improve the performance of glass-ceramics, and the Vickers hardness increases from 761.5HV to 834.8HV. The corrosion process can be divided into three stages, including reaction of glass phase with hydrofluoric acid, formation of sediment on the surface of glass-ceramics and a corrosive layer. The whole process is closely related to insoluble crystal phase, which provides a theoretical basis for the study of hydrofluoric acid processing glass/glass-ceramics.

Three-dimensional femtosecond laser inscription of type a-based high-efficiency first-order waveguide Bragg gratings

A novel type of waveguide Bragg grating (WBG) is demonstrated based on femtosecond laser-induced Type A refractive index modifications, namely based of the photochemistry of silver species in a specialty ortho-phosphate glass matrix. First-order WBGs are reported in the near-infrared and down to 736 nm in the visible. Relative transmission measurements with a 500 µm long WBGs lead to narrow-bandwidth attenuations (sub-nm spectral FWHM) from 2.29 dB to 6.25 dB for periods from 240 nm to 280 nm, respectively. The corresponding estimated backward coupling coefficients show high values from 1.66 mm-1 up to 2.69 mm-1. Additionally, we report on a true 3D helix-shaped WBG that shows an even stronger relative attenuation of 10.3 dB for a 500 µm long WBG, equivalently corresponding to a backward coupling coefficient of 3.7 mm-1. These novel results pave the way for new silver-based laser-inscribed integrated photonic devices, among which the combination of Bragg gratings to form active/passive optical resonators, but also the direct inscription of WBG at the glass interface for enhanced sensing applications.

Silver films on glass with very thin chromium adherence interlayers; reflectance and adherence at film-glass interface

Silver (Ag) thin films deposited on glass are proficient in their visible range reflectance at both Ag/air and Ag/glass interfaces. However, the film adherence onto glass is feeble due to a surface free energy disparity between the materials. Issues such as peeling, pitting, and detaching of Ag films on glass used as mirrors and prisms in various optical instruments are common. Very thin and intermittent adherence interlayers of chromium (Cr), titanium (Ti), etc, between Ag and glass resolves the issues to a substantial level. With least possible net surface area of the interlayer and a sufficient adherence of the film system the reflectance at the film/glass interface may be affected only insignificantly. This study presents an adherence optimization of Ag thin films on glass using very thin Cr interlayer with an attempt to retain its Ag/glass interface reflectance at useful levels. Adherence layers of Cr at various thicknesses from 0.4 nm to 5.0 nm and overlayer Ag films around 120 nm on silica glass were deposited by thermal evaporation in vacuum. Then the adherence and reflectance of the film system at the glass interface were evaluated using Scratch and Scotch Tape Tests and UV–visible spectrophotometric measurements. Amount and distribution of the intermittent adherence layers have been evaluated by energy dispersive X-ray photoelectron spectroscopy. 0.7 nm thick intermittent chromium interlayer between the pure silver film and the glass were found to be useful as resolving the adherence issues with a loss about 4–5% in reflectance.

Probing Surfactant Bilayer Interactions by Tracking Optically Trapped Single Nanoparticles

AbstractSingle‐particle tracking and optical tweezers are powerful techniques for studying diverse processes at the microscopic scale. The stochastic behavior of a microscopic particle contains information about its interaction with surrounding molecules, and an optical tweezer can further facilitate this observation with its ability to constrain the particle to an area of interest. Although these techniques found their initial applications in biology, they can also shed new light on microscopic interface phenomena by unveiling nanoscale morphologies and molecular‐level interactions in real time, which are obscured in traditional ensemble analysis. Here, the application of single‐particle tracking and optical tweezers are demonstrated for studying molecular interactions at solid–liquid interfaces. Specifically, the surfactant behaviors at the water–glass interface are investigated by tracing gold nanoparticles that are optically trapped on these molecules. The underlying mechanisms governing the particle motion, which can be explained by hydrophobic interactions, disruptions, and rearrangements among surfactant monomers at the interfaces, are discovered. These interpretations are further supported by statistical analysis of an individual trajectory and comparison with theoretical predictions. The findings provide new insights into the surfactant dynamics and also illustrate the promise of single‐particle tracking and optical manipulation for studying nanoscale physics and chemistry of surfaces and interfaces.

Functional refractive-index sensor by internal reflection of diffuse light

PurposeThis study aims to propose and study a refractive index sensor based on measuring variations of the internal diffuse reflectance from a glass interface in a functional design. The device is uncomplicated to assemble with simple optical elements and it can be built as a robust and stable sensor.Design/methodology/approachThis study presents a simplified theoretical model of the signal obtained with the proposed device and perform a detailed analysis of its potential resolution and merits.FindingsThe authors report proof-of-principle experiments with a home-made device to evaluate its performance as a refractometer and index of refraction sensor.Originality/valueThe main novelty of the device is the use of a diffusing surface to couple light into a glass plate with a wide range of angles of refraction, including angles larger than the critical angle with the external medium, and using the same diffusing surface to couple reflected light out of the glass plate, including light that suffered total internal reflection.