Optical Glass Research Articles

Preparation of ZTA composite ceramics derived from sol–gel method by DIW printing

AbstractIn this study, the dense and fine‐grained zirconia toughened alumina (ZTA) composite ceramics were efficiently prepared by 3D gel printing technology. Zirconia powder, zirconium oxychloride, and zirconium sol were introduced into boehmite gel as zirconium sources, and their effects on rheological properties, drying characteristics, microstructure, and mechanical properties of ceramics were discussed. The results showed that all gels exhibit reversible shear thinning properties. The gel with zirconia powder has a relaxation phenomenon; zirconium sol forms another gel network in the boehmite gel network, and two linear viscoelastic regions are observed. The gel with zirconia powder has the highest solid loading, small drying shrinkage, and fewer drying defects. The grain growth of ZTA ceramics with zirconium sol was inhibited, and the zirconia grains were evenly distributed, with the highest bending strength of 518 ± 103 MPa. The new gel preparation method and gel drying process offer great possibilities for manufacturing optical glasses and functional ceramics with high‐performance geometric structures, which cannot be achieved by traditional manufacturing methods.

Optimizing the composition of barium-borate glasses for enhancing thermal neutron shielding efficiency: Monte Carlo simulation

A transparent window with thermal neutron shielding properties was an important part of the stations of the nuclear reactors and the particle accelerators. The borate glass with a high neutron cross section was a candidate as a glass network for the neutron shielding window. In order to slow down thermal neutrons, they were trapped by boron and subsequently emitted secondary radiation, such as alpha particles and gamma-ray radiation. This work was to optimize the content between a ratio of borate with a high cross-section neutron interaction and barium for shielding alpha and gamma ray. The barium-borate glasses were successfully synthesized using the melting technique in the atmosphere. Measurements of mechanical and optical glass properties were presented. The measured results showed that an increase in barium oxide content in the glass ratio enhanced the glass density and the transmittance at a visible wavelength. In the calculation of radiation shielding properties, FLUKA code based on Monte Carlo Simulation was demonstrated. The calculated results revealed that an increase in the barium oxide content in the glass composition reduced the thermal neutron shielding properties of the glass samples. In contrast, the glass with barium contents enhanced the photon-shielding efficiency, as indicated by the mass attenuation coefficient and half-value layer. Not only the ratio of the barium and borate contents affected the shielding properties, but the increased glass thickness also enhanced the shielding properties. Thus, the utilization of cooperative borate glasses and barium with appropriate thickness could potentially serve as a viable option for simultaneously protecting against thermal neutrons and photons. The barium-borate glasses with our composition might be used as a window in a thermal neutron station as well as for photon radiation.

Construction of superhydrophobic tungsten carbide via laser processing and its thermal, chemical and mechanical properties

Designing microscale microstructures on superhard materials and achieving superhydrophobic surfaces through wettability adjustment have promising application prospects. However, current popular methods for preparing superhydrophobic surfaces have not designed and optimized the microstructures, and achieving superhydrophobicity on superhard materials using conventional industrial methods remains a tremendously challenge. Here, we propose a novel multiscale microstructure design on superhard tungsten carbide (WC) alloy material, achieved through laser processing, which exhibits superhydrophobicity after low surface energy modification. To ensure the designed microstructures possesses excellent mechanical strength and wettability, the influence of size parameters on mechanical strength and their relationship with wettability through finite element analysis (Abaqus) and characterization techniques were conducted. Based on the optimized robust multiscale structure, we also investigated the comprehensive properties of the superhydrophobic surface. The thermal, chemical, and mechanical stability of the WC superhydrophobic surface were explored through experiments involving temperature exposure, immersion in acid-base solutions, friction and wear tests. Our findings demonstrate that the superhydrophobic WC surface exhibits excellent temperature resistance over a wide range, maintaining superior water repellency even after prolonged exposure to chemical solutions and mechanical abrasion tests. In addition, the substrate's microstructure and SiO2 nanoparticles successfully replicated on the optical glass surface through molding technology, creating a consistently superhydrophobic glass microstructure. This work provides a new perspective for designing superhard alloy materials with robust microstructures and offers potential for a series of applications, such as mold, semiconductor and solar cell.

Influence of Yb3+/Ho3+ codoping on optical and thermal properties of TeO2-ZnO glass

This paper reports the effect of incorporation of Yb3+ ions on the frequency downconversion luminescence and thermal properties of triply ionised Ho3+ doped zinc tellurite (TZ) glasses. The photoluminescence spectra of both the Ho3+/Yb3+ doped and codoped glasses have been recorded and observed a green emission band corresponding to the 5F4, 5S2 → 5I8 (∼550 nm) transition upon various excitations. In the downconversion (DC) emission process, the back energy transfer (BET) mechanism from Ho3+ ions to Yb3+ ions has also been explored. The colour emitted in the downconversion process is found to be non-tunable at different excitations. Thus, the Ho3+:TZ glass can be utilised for non-colour tunable optical devices under various UV excitations. Also the glass transition (Tg) and crystallisation (Tc) temperatures have been measured for both the doped and codoped glasses and found to be increased in the codoped glass. The singly Ho3+ions doped TZ glass shows better optical downconversion and glass forming ability.

GeO2-based novel optical glasses with high refractive index, large mid-infrared transmission, and low thermal expansion

GeO2-based novel optical glasses with high refractive index, large mid-infrared transmission, and low thermal expansion

Solmers: Versatile hybrid resins for nanometric 3D printing of silica-based photonic components

Owning to their intrinsic properties, silica-based glasses are widely used in various technological fields, especially in photonics. However, high degree of flexibility is yet challenging in realization of next-generation miniaturized optical components. In this work, we develop an approach based on ‶Solmers″ hybrid resins allowing versatile two-photon polymerization 3D printing of silica glasses with 23 nm resolution, doping with Germanium and/or rare-earths elements. Other dopants such as gold nanoparticles were also incorporated for localized metallization. After 3D printing and sintering (1100–1300 °C), high optical quality glasses with low surface roughness (<0.2 nm) were obtained. Structural analyses confirmed the amorphous structure of silica glasses. Various mono- or multi-materials microstructures were successfully fabricated on fused silica substrates. Besides, this approach was extended to the functionalization of optical fibers for optical sensing applications in harsh environment (1000 °C). Compared to organic or organic-inorganic materials, these dense silica-based glasses with enhanced optical and structural properties will open new avenues for the development of emerging advanced optical components.

Design method for lens desensitization adapted to refractive index error

The design of optical systems not only considers the imaging performance but also the manufacturing difficulty and feasibility of the system. In practice, errors in the manufacturing process of glass materials and deviations in glass material parameters introduced in complex environments can both lead to degradation in the imaging quality of optical systems. Optical systems that are sensitive to glass material errors face increased manufacturing difficulty and reduced stability. This paper, based on geometrical optics theory, establishes an evaluation function for refractive index error sensitivity and analyzes its relationship with optical parameters and glass materials. It proposes a design method to reduce the refractive index sensitivity of optical systems. Through simulation verification and analysis using examples, the validity of the desensitization design method is confirmed.

Micro-Grinding Parameter Control of Hard and Brittle Materials Based on Kinematic Analysis of Material Removal

This article explores the intricacies of micro-grinding parameter control for hard and brittle materials, with a specific focus on Zirconia ceramics (ZrO2) and Optical Glass (BK7). Given the increasing demand and application of these materials in various high-precision industries, this study aims to provide a comprehensive kinematic analysis of material removal during the micro-grinding process. According to the grinding parameters selected to be analyzed in this study, the ac-max values are between (9.55 nm ~ 67.58 nm). Theoretical modeling of the grinding force considering the brittle and ductile removal phase, frictional effects, the possibility of grit to cut materials, and grinding conditions is very important in order to control and optimize the surface grinding process. This research introduces novel models for predicting and optimizing micro-grinding forces effectively. The primary objective is to establish a micro-grinding force model that facilitates the easy manipulation of micro-grinding parameters, thereby optimizing the machining process for these challenging materials. Through experimental investigations conducted on Zirconia ceramics, the paper evaluates a mathematical model of the grinding force, highlighting its significance in predicting and controlling the forces involved in micro-grinding. The suggested model underwent thorough testing to assess its validity, revealing an accuracy with average variances of 6.616% for the normal force and 5.752% for the tangential force. Additionally, the study delves into the coefficient of friction within the grinding process, suggesting a novel frictional force model. This model is assessed through a series of experiments on Optical Glass BK7, aiming to accurately characterize the frictional forces at play during grinding. The empirical results obtained from both sets of experiments—on Zirconia ceramics and Optical Glass BK7—substantiate the efficacy of the proposed models. These findings confirm the models’ capability to accurately describe the force dynamics in the micro-grinding of hard and brittle materials. The research not only contributes to the theoretical understanding of micro-grinding processes but also offers practical insights for enhancing the efficiency and effectiveness of machining operations involving hard and brittle materials.

Simulation and experimental investigation of material removal profile based on ultrasonic vibration polishing of K9 optical glass

Ultrasonic vibration polishing (UVP) is an important method for the precision processing of optical glass, which is good for improving surface quality and processing efficiency. So far, the material removal mechanism in UVP is not well understood and the various process parameters involved are not considered. To achieve ultra-precision polishing under optical glass, this paper carries out the axial UVP method. The material removal profile (MRP) is critical to affect the surface accuracy. A new MRP is developed for UVP based on the Urick attenuation model and the proposed material removal coefficient distribution function, considering the dynamic pressure changes under ultrasonic vibration, the attenuation effect of the acoustic pressure propagation process and the inhomogeneous distribution of the abrasive particles in the contact area during the ultrasonic electro-spindle rotation. Through a series of polishing experiments and simulations, the results show that the maximum errors of the actual material removal depth (MRD) and the actual material removal rate (MRR) from the model simulation results are 8.54% and 9.92%, respectively. The accuracy of the model is further demonstrated by the Pearson correlation coefficient. When the amplitude of UVP is 9 µm, Sa and Ra are 60 nm and 68 nm, which are reduced by 37.50% and 22.73%, respectively, compared with conventional polishing. This research can contribute to the deterministic processing of UVP, and provide a theoretical basis for the application of optical glass.

Exploring luminescence dynamics in Ce3+/Er3+ co-doped lithium zinc barium borate optical glasses: A study for advancing photonic technologies

Lithium zinc barium borate glasses were synthesized using the melt-quenching method and doped with Ce3+, Er3+, and their combination. The study examines the influence of Ce3+ on the photoluminescence of Er3+ in these glasses. X-ray diffraction confirmed the amorphous nature of both undoped and doped glasses, while Fourier-transform infrared spectroscopy showed the conversion of BO3 to BO4 units, and Raman spectroscopy indicated a phonon energy around 1136 cm−1. The Ce3+-doped glasses exhibited a blue emission at 447 nm due to the 5d→4f1 transition. Co-doping with Ce3+ and Er3+ led to decreased visible upconversion emissions but significantly enhanced near-infrared emissions at 1.53 μm. This enhancement is attributed to reduced non-radiative decay and improved energy transfer between Er3+ and Ce3+ ions, facilitated by the phonon energy of host glass. The 1.53 μm emission intensity in Ce3+/Er3+ co-doped glass was about 60% higher than in singly Er3+-doped samples, highlighting the potential of Ce3+ co-doping for broad amplification at 980 nm excitation.

Chemical etching-assisted femtosecond laser multi-beam rapid preparation of As2Se3 microlens arrays

Chalcogenide glass has gradually evolved into a new generation of infrared optical glasses. As2Se3, a representative chalcogenide glass in the mid-infrared wavelength band, is commonly used in the production of infrared optical devices. In this paper, we primarily used femtosecond laser multi-beam parallel processing technology, complemented by chemical etching technology, to efficiently manufacture infrared microlens arrays with exceptional optical morphology. By adjusting parameters such as the number of laser beam splits, beam spacing, energy, and pulse count, we were able to produce a range of microlens arrays with varying diameters, depths, and filling ratios. Finally, we use the optical imaging test system to focus and capture images of the fabricated microlens arrays, demonstrating excellent optical performance. This processing technology has broad application prospects in the middle infrared band, such as military, medical, and other fields.

Brake Fluid Condition Monitoring by a Fiber Optic Sensor Using Silica Nanomaterials as Sensing Components.

In the automotive industry, there has been considerable focus on developing various sensors for engine oil monitoring. However, when it comes to monitoring the condition of brake fluid, which is crucial for ensuring safety, there has been a lack of a secure online method for this monitoring. This study addresses this gap by developing a hybrid silica nanofiber mat, or an aerogel integrated with an optical fiber sensor, to monitor brake fluid condition. The incorporation of silica nanofibers in this hybrid enhances the sensitivity of the optical fiber glass surface by at least 3.75 times. Furthermore, creating an air gap between the glass surface of the optical fiber and the nanofibers boosts sensitivity by at least 5 times, achieving a better correlation coefficient (R2 = 0.98). In the case of silica aerogel, the sensitivity is enhanced by 10 times, but this enhancement relies on the presence of the established air gap. The air gap was adjusted to range from 0.5 mm to 1 mm, without any significant change in the measurement within this range. The response time of the developed sensor is a minimum of 15 min. The sensing material is irreversible and has a diameter of 2.5 mm, making it easily replaceable. Overall, the sensor demonstrates strong repeatability, with approximately 90% consistency, and maintains uncertainty levels below 5% across specific ranges: from 3% to 6% for silica aerogel and from 5% to 6% for silica nanofibers in the presence of an air gap. These findings hold promise for integrating such an optical fiber sensor into a car's electronic system, enabling the direct online monitoring of brake fluid quality. Additionally, the study elucidates the effect of water absorption on the refractive index of brake fluid, as well as on the silica nanomaterials.

Fast, Precise, High Contrast Laser Writing for Photonic Chips with Phase Aberrations

AbstractIntegrated photonic chips have significant potential in telecommunications, classic computing, quantum systems, and topological photonics. Direct laser writing offers unique capability for creating three‐dimensional photonic devices in an optical glass chip with quick prototyping. However, it is a challenge for existing laser writing schemes to create index‐modified structures in glass that precisely match the laser focal shape while also achieving high refractive index contrasts and high scanning speeds. Here, we introduce a refractive index modification scheme that combines the advantages of non‐thermal and thermal regime fabrication methods. We also propose a waveguide formation model that is verified through a thorough study on the effects of phase aberrations. The presented new photonic chip fabrication scheme uses a novel focal intensity distribution, where pulse energy is relocated to the bottom of a laser focus by manipulating primary and higher order spherical aberrations. The technique can produce index modifications with high scanning speed (can be 20 mm/s or higher), high index contrast (ranging from 0.009 to 0.021), and high precision to fabricate with arbitrary cross‐sections. This method has potential to expand the capabilities of photonic chips in applications that require small‐scale, high precision, or high contrast refractive index control.

Research of dispersion characteristics of optical glass

Research of dispersion characteristics of optical glass

Contrastive Analysis of Interferometric Techniques for Small Channel Temperature Measurements

This research employs a state-of-the-art digital interferometric technique to investigate the temperature distribution within a confined rectangular channel, with a hydraulic diameter of 3 mm. The experimental setup incorporates an optical glass channel, with nanofluids (Aluminium oxide) as the test fluid at 0.001% volume concentration. To induce controlled heating, a heater filament is strategically placed along the bottom wall of the channel. Simultaneously, a T-type thermocouple is carefully placed to measure the temperature along the upper wall. Two distinct interferometric methods, namely the Michelson interferometer and the Mach-Zehnder interferometer, are employed to capture the complex details of fringes resulting from the evolving temperature field within the test section. A high-resolution CCD camera is employed to capture these fringes, and sophisticated digital image processing techniques are subsequently applied for in-depth fringe analysis. The culmination of these efforts results in the origin of a comprehensive localized temperature distribution map within the small-sized channel. The obtained temperature profiles are meticulously compared, providing valuable insights into the effectiveness and reliability of the Michelson and Mach-Zehnder interferometric techniques in this specific experimental context. This detailed comparative analysis contributes to the broader understanding of interferometric methods for temperature measurements in confined fluidic systems.

THE DEVELOPMENT OF THE OPTICAL INDUSTRY OF THE USSR IN THE SECOND HALF OF THE 1940S - MID-1960S UNDER THE CONDITIONS OF TRANSITION TOWARDS LATE INDUSTRIAL MODERNIZATION

The purpose of the research. The purpose of the research work was to study the history of optics as one of the high-tech industries of production and science in the context of the transition to late industrial modernization. The topic is actualized by the modern conditions of the formation of the post-industrial economy and the need for import substitution in the face of sanctions pressure. Results. In the second half of the 1940s - mid-1960s, having carried out re-evacuation and reconversion, the optical and mechanical industry of the USSR expanded its production and scientific base, mastered new types of optical products, and improved optical glass production technologies. The scientific and technological revolution has led to the emergence of new high-tech industries in need of high-tech optical devices (space industry, electronics, photo-film industry). In the second half of the 1940s - mid-1960s. The Soviet industrial modernization in optics was entering its final stage, and the fourth technological order was taking shape, within the framework of which there was a proliferation of conveyor production, laser technology, alignment equipment, and programmable machine tools. By the mid-1960s, the country was well-off in competition with the West in optical technologies, the USSR produced high-precision optical devices for export. The successes of the optical and mechanical industry and science created the prerequisites for the transition of the Soviet Union to a post-industrial economy.

Optical storage and encryption via efficient reversible luminescence modulation based on copper-doped borate glass

Transparent glass is a promising candidate for optical storage media due to its large capacity and high stability advantages. Previously reported optical storage glass systems meet various problems, such as high manufacturing costs, low security levels, etc. Herein, a kind of copper-contained borate glass was designed and fabricated, emitting tunable broadband upon various ultraviolet light excitations. By alternating 360 nm laser (10.7 W/cm2) irradiation for 15 s and thermal treatment at 400 ℃ for 2 h, the emission intensity of the glass can be reversibly regulated, which is associated with the variation of oxidation states of the copper element. Relying on their efficient reversible luminescence modulation behaviors, the potential application of this glass as an optical storage and encryption media is developed, exhibiting the high performances of repeatable writing and erasing, dual mode readout, high-level safety, and good writing resolution for the Cu-doped borate glass.

Measuring gloss using spectral reflectance

Abstract Gloss is historically measured at three angles of incidence, 20°, 60°, and 85°, using a light source filtered to replicate Illuminant C and a colored glass filter designed to reproduce the CIE 1931 photopic luminous efficiency function. Herein an alternate method that relies on the spectral reflectance of a gloss standard and the sample, both measured with a new reference gonio-spectrometer and in accordance with the geometries specified in internationally recognized standards, is presented. The spectral reflectance measured with the aid of a spectrometer is converted to luminous flux which is then used to calculate gloss. This alternate method eliminates the errors associated with the source actual spectral power distribution vs. that of Illuminant C, and the actual spectral transmittance of the colored glass filter used vs. the spectral distribution of the photopic luminous efficiency function. Gloss measurement results for a synthetic quartz sample, Suprasil 311, are presented. The measured values averaged over three reflectance measurements are 71.3 ± 1.2 (k = 2), 82.2 ± 0.9 (k = 2), and 98.1 ± 3.0 (k = 2), and these agree exceptionally well with the theoretical values of 71.3, 82.1, and 98.1 Gloss Units at 20°, 60°, and 85°, respectively. Components of uncertainty are discussed. In addition, a gloss scale is proposed. The components of the scale have been selected from readily available optical glass types for ease of fabrication and relatively low cost. They span a range from 4.4 to almost 170 Gloss Units for light at 20° angle of incidence.

Effect of Deposition Working Power on Physical Properties of RF-Sputtered CdTe Thin Films for Photovoltaic Applications.

The main objective of this study was to determine the variation in the properties of cadmium telluride (CdTe) thin films deposited on a p-type Si substrate by the radio frequency magnetron sputtering technique at four different working powers (70 W, 80 W, 90 W, and 100 W). The substrate temperature, working pressure, and deposition time during the deposition process were kept constant at 220 °C, 0.46 Pa, and 30 min, respectively. To study the structural, morphological, and optical properties of the CdTe films grown under the mentioned experimental conditions, X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and optical spectroscopy were used. For a better analysis of the films' structural and optical properties, a group of films were deposited onto optical glass substrates under similar deposition conditions. The electrical characterisation of Ag/CdTe/Al "sandwich" structures was also performed using current-voltage characteristics in the dark at different temperatures. The electrical measurements allowed the identification of charge transport mechanisms through the structure. New relevant information released by the present study points towards 90 W RF power as the optimum for obtaining a high crystallinity of ~1 μm nanostructured thin films deposited onto p-Si and optical glass substrates with optical and electrical properties that are suitable for use as absorber layers. The obtained high-quality CdTe nanostructured thin films are perfectly suitable for use as absorbers in CdTe thin-film photovoltaic cells.

Lifespan prediction procedure of volume nanogratings imprinted by femtosecond laser in optical glasses

Volume nanogratings imprinted by infrared femtosecond laser in oxide glasses exhibit a characteristic birefringent signature, which translates into measurable retardance. Upon thermal annealing, such signature is progressively erased, typical of nanograting erasure. In this work, we propose a procedure to predict the lifespan of nanogratings by two main approaches: 1/ numerical modeling of optical retardance ageing using the Rayleigh-Plesset equation, and 2/exploiting VAREPA (VAriable REaction PAthways) framework fed by simulated ageing data. By considering experimental time – temperature annealing conditions, the modeled retardance is gathered as a function of demarcation energy to build a so-called Master Curve and then compared to accelerated ageing experiments. The erasure constant rate k0 can be determined for 8 commercial optical glasses. Based on a distributed Rayleigh-Plesset model, k0 and activation energy distribution are linked to glass viscosity and its temperature dependency. Finally, we discussed the restrictions on VAREPA application for an accurate lifetime prediction. This work provides guidelines for the future development of nanogratings based devices and applications, including optical data storage, birefringent devices, and optical sensors, through a judicious choice of glass composition and associated properties.