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Quartz material irradiated by femtosecond laser has increasingly attracted widespread attention for the micro-fabrication of photonic devices. Mechanism exploration is beneficial for accelerating the digital progress of laser processing. However, the mechanism between femtosecond laser and quartz is complicated and needs further theoretical investigation. This paper established the theoretical model based on the ionization model with the Drude equation to study the space–time evolution of free electron density and its influence on the absorption coefficient, reflectivity, and ablation depth. In addition, we achieved a 10 × 10 micro-holes array with a pore size less than 10 μm, cone angle less than 2° in a 0.25 mm thick quartz on the condition of a laser pulse energy Ep = 3 μJ, scanning velocity v = 0.1 mm/s, and defocusing distance Δf = −0.3 mm via the bottom-up femtosecond laser processing. The work gives a new insight into further understanding the ablation mechanism of transparent materials etching by the femtosecond laser. It provides a practical technical scheme for preparing commercial quartz photonic devices. [ABSTRACT FROM AUTHOR]

This study advances glass nanocomposite research by achieving exceptional Electromagnetic Interference (EMI) shielding while maintaining optical transparency. We employ femtosecond laser engraving and thermal vapor deposition to create precise periodic line patterns on fused quartz glass, which serve as a framework for the controlled deposition of silver (Ag) and gold (Au) nanoparticles through laser-ablated micro-channels. These nanocomposites effectively balance EMI shielding and optical transmittance, making them suitable for applications in electronics, aerospace, and telecommunications. Femtosecond laser ablation allows for meticulous glass surface modification. Using an XY motorized translation stage guided by a photoresist, we form line patterns with spacings of 200, 400, and 600 µ-meter, resulting in Shielding Effectiveness (SE) in the range of 10–37 dB. Notably, despite substantial modification, the glass nanocomposites retain optical transmittance comparable to clear glass, enhancing their utility in applications where visual clarity is essential, such as windows, displays, and security infrastructure. By integrating femtosecond laser ablation with controlled thermal deposition, we produce multifunctional glass nanocomposites that offer promising EMI shielding and optical transparency, paving the way for advanced materials in industries where both properties are critical. [ABSTRACT FROM AUTHOR]

GaN has a wide application prospect in optoelectronics, semiconductor lighting and other fields because of its superior physical and electrical attributes. The in-depth research of the preparation and processing technology of GaN is particularly important. However, traditional GaN processing methods have limitations in processing, such as high processing difficulty and limited processing accuracy. Laser processing is a high-precision, non-contact, non-thermal carrier damage processing method that is widely employed for the growth and processing of GaN. Progress in GaN laser processing over the last few years is reviewed in this paper,focusing on laser etching of GaN and laser growth of GaN, including laser epitaxial growth technology, laser pulsed deposition technology and laser stripping transfer technology. Finally, the future development direction and challenges of laser growing and processing of GaN are prospected. Laser growth and processing techniques for GaN are expected to expand the range of applications for GaN devices. [ABSTRACT FROM AUTHOR]

Superhydrophobic paper-based functional materials have emerged as a sustainable solution with a wide range of applications due to their unique water-repelling properties. Inspired by natural examples like the lotus leaf, these materials combine low surface energy with micro/nanostructures to create air pockets that maintain a high contact angle. This review provides an in-depth analysis of recent advancements in the development of superhydrophobic paper-based materials, focusing on methodologies for modification, underlying mechanisms, and performance in various applications. The paper-based materials, leveraging their porous structure and flexibility, are modified to achieve superhydrophobicity, which broadens their application in oil–water separation, anti-corrosion, and self-cleaning. The review describes the use of these superhydrophobic paper-based materials in diagnostics, environmental management, energy generation, food testing, and smart packaging. It also discusses various superhydrophobic modification techniques, including surface chemical modification, coating technology, physical composite technology, laser etching, and other innovative methods. The applications and development prospects of these materials are explored, emphasizing their potential in self-cleaning materials, oil–water separation, droplet manipulation, and paper-based sensors for wearable electronics and environmental monitoring. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to investigate the effect of laser etching, air bone particle abrasion and acid etching on shear bond strength between re-cast Nickel Chromium alloy and dental ceramics. Materials and Methods: A master die was made according to ISO 9693; TR (11406). A total of 40 samples were fabricated with 50%w nickel-chromium alloy and 50%w previously casted nickel-chromium alloy. The samples were divided into four groups based on the surface treatment applied. Group 1 served as the untreated control, Group 2 underwent etching with 10% hydrochloric acid (HCl), Group 3 received surface treatment via air-borne particle abrasion, while Group 4 was conditioned using a pulsed Nd:YAG laser. Shear bond strength between ceramic and metal was tested using a universal testing machine and the mode of debonding was evaluated using scanning electron microscope. The obtained values were statistically analyzed using one-way ANOVA and Tukey's HSD Post Hoc test. Results: The mean values of shear bond strength for Group 1 was 22.69±2.63Mpa, Group 2 was 27.05±2.15Mpa, Group 3 was 34.46±2.46Mpa and Group 4 was 39.54±2.16Mpa. The difference among the groups was significant (P<0.001). Hence there was a statistical difference seen in shear bond strength between control and acid etching, air borne particle abrasion and laser etching. Conclusion: Laser surface conditioning produced more surface roughness compared to acid etching and air bone particle abrasion on re-cast Nickel Chromium alloy which increased the shear bond strength markedly between recast nickel-chromium alloy and dental Ceramic. [ABSTRACT FROM AUTHOR]

The development of mechanically robust super-lubrication hydrogel materials with sustained lubricity at high contact pressures is challenging. In this work, inspired by the durable lubricity feature of the earthworm epidermis, a multilevel structural super-lubrication hydrogel (MS-SLH) system, the so-called lubricant self-pumping hydrogel, is developed. The MS-SLH system is manufactured by chemically dissociating a double network hydrogel to generate robust and wrinkled lubrication layer, and then laser etching was used to generate cylindrical texture pores as gland-like pockets for storing lubricants. The surface of MS-SLH system shows ultrafast hydration characteristics and reversible pore-closing and pore-opening behavior. The current MS-SLH system shows excellent SL features, as follows: a very low COF (~0.0079) at high contact pressure condition (P: 11.32 MPa); a stable and robust SL lifespan (COF: ~0.0028, P: 8.48 MPa, 100k cylces) without surface wear; and a sustained lubricity period (3700 cycles) with limited lubricant volume (5 μL) in air. The robust and sustained lubricity of the MS-SLH system is likely attributed to the synergy from the strong electrostatic repulsion effect at the sliding interface, the robust but compliant modulus of the dissociation lubrication layer, and the self-pumping lubricant release from the gland-like pocket of the texture pores during the dynamic shearing process. The demonstration experiments based on self-built equipments intuitively exhibit durable SL behavior of MS-SLH system. This work provides an easy strategy for the large-scale manufacture of high-performance water-lubrication coatings suitable for high-end medical devices or moving parts. Developing mechanically robust hydrogels with high lubricity is challenging but desirable. Here, the authors report the development of a layered hydrogel with a robust and wrinkled lubrication layer, and pores for storing lubricants, for sustained lubricity. [ABSTRACT FROM AUTHOR]

Weathered crust karst reservoirs with intricately interconnected fractures and caves are common but challenging enhanced oil recovery (EOR) targets. This paper investigated the remaining oil distribution rules, formation mechanisms, and EOR methods through physical experiments on acrylic models resembling the geological features of weathered crust reservoirs. Acrylic models with precision dimensions and morphologies were fabricated using laser etching technology. By comparing experiments under different cave filling modes and production well locations, it was shown that a higher cave filling extent led to poorer bottom water flooding recovery due to stronger flow resistance but slower rising water cut owing to continued production from the filling medium. Multi-well water and gas injection achieved higher incremental oil recovery by alternating injection–production arrangements to establish new displacement channels and change drive energy. Gas injection recovered more attic remaining oil from upper cave regions, while subsequent water injection helped wash the residual oil in the filling medium. The findings reveal the significant effects of fracture cave morphological configuration and connectivity on remaining oil distribution. This study provides new insights and guidance for EOR design optimization catering to the unique features of weathered crust karst fractured vuggy reservoirs. [ABSTRACT FROM AUTHOR]

In microfluidic chips, glass free-form microchannels have obvious advantages in thermochemical stability and biocompatibility compared to polymer-based channels, but they face challenges in processing morphology and quality. Hence, picosecond laser etching with galvanometer scanning is proposed to machine spiral microfluidic channels on a glass substrate. The objective is to disperse and sort microparticles from a glass microchip that is difficult to cut. First, the micropillar array and the spiral microchannel were designed to disperse and sort the particles in microchips, respectively; then, a scanning path with a scanning interval of 5 μm was designed according to the spot diameter in picosecond laser etching; next, the effects of laser power, scanning speed and accumulation times were experimentally investigated regarding the morphology of spiral microchannels; finally, the microfluidic flowing test with 5 μm and 10 μm microparticles was performed to analyze the dispersing and sorting performance. It was shown that reducing the laser power and accumulation times alongside increasing the scanning speed effectively reduced the channel depth and surface roughness. The channel surface roughness reached about 500 nm or less when the laser power was 9 W, the scanning speed was 1000 mm/s, and the cumulative number was 4. The etched micropillar array, with a width of 89 μm and an interval of 97 μm, was able to disperse the different microparticles into the spiral microchannel. Moreover, the spiral-structured channel, with an aspect ratio of 0.51, significantly influenced the velocity gradient distribution, particle focusing, and stratification. At flow rates of 300–600 μL/min, the microparticles produced stable focusing bands. Through the etched microchip, mixed 5 μm and 10 μm microparticles were sorted by stable laminar flow at flow rates of 400–500 μL/min. These findings contribute to the design and processing of high-performance glass microfluidic chips for dispersion and sorting. [ABSTRACT FROM AUTHOR]

As an environment-friendly material, graphene oxide nanosheet can effectively improve the polishing surface quality of single crystal diamond workpieces. However, the lubricating and chemical effects of graphene oxide nanosheets have an uncertain impact on the polishing material removal rate. In this paper, the graphene oxide-enhanced hybrid slurry was prepared with good stability. The femtosecond laser etching and contour measurement method was adopted to analyze the polishing material removal rate of the CVD single crystal diamond workpiece. The surface damage of the workpiece polished with SiC abrasive grains is minimal, while the workpiece with diamond abrasive grains has the largest material removal rate. With an increase in abrasive grain size, the polishing material removal rate increases, but new surface scratches and pits can be introduced if the grain size is too large. Therefore, a grain size of 2.5 μm was selected to improve the surface quality. The surface roughness first decreases and then increases with the increase in polishing rotation speed. At a speed of 4000 rpm, the surface roughness reached its minimum with a relatively high material removal rate simultaneously. A series of CVD single crystal diamond scratching experiments were conducted with different scratching speeds, which proved that graphene oxide can help facilitate material surface micro-protrusion removal. [ABSTRACT FROM AUTHOR]

During liquid metal embrittlement a liquid metal infiltrates grain boundaries of a compatible solid metal, interrupting the inter-grain bonds and weakening the metal. Ongoing research has proposed that this effect may be used to perform additive/subtractive hybrid machining to fabricate replacement components, using relatively simple equipment and low material and instrument costs. The gallium/aluminum pairing is of particular interest due to the usage of aluminum in a wide variety of structural and aerospace applications coupled with gallium's nontoxicity and melting point just above room temperature, which facilitates storage and transport. To activate aluminum to gallium infiltration, the surface oxide formed on aluminum in atmosphere must first be removed simultaneously with a significant amount of bulk metal to promote flow control of the liquid metal. Three targeted techniques for oxide removal were tested and compared, specifically mechanical abrasion, chemical etching, and laser ablation. Mechanical abrasion is simple to implement but lower precision. Chemical etching requires significant prep work and cleanup but could operate on entire sheets of substrate simultaneously with proper masking. Although laser ablation requires the most complex instrumentation, it requires minimal prep work and provides the greatest precision, making it ideal for the manufacturing application under development here. [ABSTRACT FROM AUTHOR]

Designing and fabricating a highly sensitive non-enzymatic glucose sensor is crucial for the early detection and management of diabetes. Meanwhile, the development of innovative electrode substrates has become a key focus for addressing the growing demand for constructing flexible sensors. Here, a simple one-step laser engraving method is applied for preparing laser-induced graphene (LIG) on polyimide (PI) film, which serves as the sensor substrate. NiCo-layered double hydroxides (NiCo-LDH) are synthesized on LIG as a precursor, utilizing the zeolitic imidazolate framework (ZIF-67), and then reacted with Ni(NO3)2 via solvent-thermal methods. The sensitivity of the non-enzymatic electrochemical glucose sensor is significantly improved by employing NiCo-LDH/LIG as the sensing material. The porous and interconnected structure of NiCo-LDH, derived from ZIF-67, enhances the accessibility of electrochemically active sites, while the incorporation of LIG ensures exceptional conductivity. The combination of NiCo-LDH with LIG enables efficient electron transport, leading to an increased electrochemically active surface area and enhanced catalytic efficiency. The fabricated electrode achieves a low glucose detection limit of 0.437 μM and demonstrates a high sensitivity of 1141.2 and 631.1 μA mM−2 cm−2 within the linear ranges of 0–770 μM and 770–1970 μM, respectively. Furthermore, the NiCo-LDH/LIG glucose sensor demonstrates superior reliability and little impact from other substances. A flexible integrated LIG-based non-enzymatic glucose sensor has been developed, demonstrating high sensitivity and suggesting a promising application for LIG-based chemical sensors. [ABSTRACT FROM AUTHOR]

This study evaluated the influence of infrared laser radiation produced by a CO2 laser, performing under different engraving parameters, on the colour changes and chemical composition of a beech wood surface. The results showed that the lightness clearly decreased with increasing laser power and density. At the highest laser power and the highest raster density, the ΔL* value was 51.3. The values of coordinates a* and b* moderately increased up to a raster density of 5 mm−1; then, with a subsequent raster density increase, the values of these coordinates decreased again. However, the coordinate values were positive in all cases. Even the lowest laser power and raster density resulted in conspicuous discolouration or even a completely new colour compared to the original (ΔE = 10) of the beech wood surface. Further increases in the laser power and raster density resulted in progressively pronounced colour differences and a darker brown colour of the surface. The ATR-FTIR chemical analysis of the beech wood surface revealed that discolouration was mainly caused by heat-induced processes associated with the degradation of carbonyl groups (C=O) in lignin and hemicelluloses. The splitting of C=O bonds induced changes in the content of chromophores responsible for the natural wood colour and for the engraving-related discolouration. The study demonstrates that the amount of energy supplied onto the wood surface by a laser beam using diverse combinations of radiation parameters can be represented by a single variable: the total irradiation dose. The functional relation detected between this variable and the colour differences may serve as a basis for using a controlled laser beam for targeted wood surface discolouration to improve the quality of patterns transferred onto a wood surface. Knowledge of this relation will enable the targeted setting of the laser parameters during engraving so that the laser beam can be used as a tool for transferring high-quality patterns onto wood surfaces. [ABSTRACT FROM AUTHOR]

Laser‐induced graphene (LIG) and laser‐induced reduced graphene oxide (LIrGO) are two relatively recent graphene‐based nanoscale materials suitable for miniaturized flexible supercapacitors. This study employs direct laser engraving techniques to generate patterns on flexible substrates, such as paper and polyamide (PI). This methodology allows fine control over the formed nanographene structures to fabricated LIG and LIrGO supercapacitors. The LIG on PI exhibits a distinctive porous structure and high surface area, adsorption, and transportation of ions. Furthermore, paper‐based LIrGO electrodes are recyclable and are formed in a single step. The morphological study is done using scanning electron microscopy, Raman spectroscopy, X‐ray photoelectron spectroscopy, and X‐ray diffraction. Galvanostatic charge–discharge studies at 0.05 mA cm−2 current density show an areal capacitance of 3.69 mF cm−2 for LIG and 1.61 mF cm−2 for LIrGO. The comparable energy densities for LIG and LIrGO are 0.32 and 0.16 μWh cm−2, respectively. From the calculative analysis of both types, the variation in specific areal capacitance enabling effective is 56.3% from GCD, indicating that the LIG device performs better. Finally, a portable potentiostat is employed to investigate the viability of utilizing supercapacitors to operate self‐powered sensors in a portable and integrable fashion. [ABSTRACT FROM AUTHOR]

The reduction of drag for both aircraft and underwater equipment has the potential to reduce their overall energy consumption. Consequently, research into the drag-reducing performance of metal surfaces has significant practical applications. However, there has been more research on the machining of grooves on flat surfaces and inside tubes and less research on the structure of drag-reducing grooves on the outside of circular rods. This paper presents a study in which laser etching technology is employed to machine a range of secondary fractal topologies and V-groove composite structures on the surface of equal-diameter stainless-steel bodies of revolution. The influence of different parameters on the surface properties of stainless-steel materials is analysed through the use of auxiliary positioning tools, adjustments to laser processing parameters and scanning path schemes, as well as the characterisation of the surface morphology of the processed stainless steel using super-depth microscopy, scanning electron microscopy, and other techniques. Subsequently, an underwater drag-reduction tester is employed to assess the drag-reduction efficacy of the optimised secondary fractal composite structure on the surface of the stainless-steel equal-diameter body of revolution. Subsequently, particle image velocity (PIV) tracking technology is employed to assess the surface flow field velocity and overall velocity average of the secondary fractal composite structure. The findings indicate that the secondary fractal composite structure exhibited a drag-reduction effect on the surface of the stainless-steel body of revolution only when the primary main groove had a width of 0.1 mm. Furthermore, an increase in the Reynolds number Re within the range of 4000 to 7000 resulted in a notable enhancement in the drag-reduction efficacy of the secondary fractal composite structure on the surface of the stainless-steel body of revolution. At Re values of 5000, 6000, and 7000, the corresponding drag-reduction rates were observed to be 5.15%, 5.28%, and 5.40%, respectively. [ABSTRACT FROM AUTHOR]

The growth of diamond film with texture on stainless steel can significantly improve its wear properties, while conventional methods such as laser etching and ultrasonic vibration superimposed machining suffered from complex processes and extra equipment. Here, we propose a simple new method to prepare textured diamond film on stainless steel without any special apparatus. In this method, a W/W-N interlayer was first deposited on the stainless steel surface, and then the sample with the interlayer was put into a hot filament chemical vapor deposition (HFCVD) chamber to grow diamond films. The interlayer becomes cracked during the warm-up stage due to the large tensile stress formed by the thermal expansion coefficient difference between the interlayer and the steel. Then the deposited diamond films copy the morphology of the interlayer, forming the textured diamond film. The textured diamond film exhibits a small amount of stress, ~3.4 GPa, and greatly improved wear resistance. Our results provide a way to prepare textured diamond films with good wear resistance. [ABSTRACT FROM AUTHOR]

In selective laser etching for the interfacial strengthening of Fiber Metal Laminates (FMLs), the wettability of customized structured features significantly affects their overall mechanical properties. For two-level features, their complicated geometry makes the evaluation of wettability difficult, which introduces challenges to feature design. In this study, a sandwich FMLs comprising an AA2024-O metal skin and a plain-woven carbon-fiber fabric core is investigated. Three types of two-level feature interfaces are designed and introduced into the FMLs structure. To understand the effect of two-level features on the resin flow and dynamic wetting progress in resin transfer molding, two-phase flow Computational Fluid Dynamics numerical models coupled with porous media and level-set numerical methods are built. The feasibility of the numerical simulation in the qualitative analysis was verified by comparing the results with those of the testing porosity values from X-ray scanning. In addition, the mechanisms of pore formation and transportation are revealed. These results indicate that the deeper groove structure in the etched features plays an important role in discharging residual air and determining the transformation of pores to reduce porosity. The permeability orientations of the porous media and surface structure both have significant impacts on the flow behavior and formation of pores. [ABSTRACT FROM AUTHOR]

The results of the study of radiation produced by the electrical explosion of Al foil with a thickness of 4 μm with an artificial periodic structure of periodic holes with 50–400 μm steps created by laser engraving are presented. The experiments were carried out on a KING pulse high-current generator (220 kA, 40 kV, 300 ns). Images of exploded foils were recorded using pinhole cameras with a 20 μm aperture on a four-frame microchannel plate camera with 5 ns temporal resolution. In experiments on the electrical explosion of thin foils, it was shown that the application of an artificial periodic structure to the foil leads to a much more uniform radiation in the UV spectrum range along the entire length and width of the foil. Uniform radiation was observed from 20 to 70 ns. It is shown that such radiation can be used for the imaging of test objects or plasma objects like exploded wires. [ABSTRACT FROM AUTHOR]

Traditional tooth preparation can cause patient discomfort, thermal damage to tissues, and occupational health risks for clinicians. Laser-based techniques, particularly femtosecond lasers, offer an alternative due to precise, non-invasive treatment without the thermal and mechanical drawbacks. The objective of this study was to assess available evidence on the effects of femtosecond laser treatment on enamel and dentin. The study design included in vitro or in vivo studies on human teeth reporting on qualitative and quantitative parameters of laser-dental tissue interaction. The review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) statement. The review was registered in the Open Science Framework registry. A comprehensive literature search of PubMed, Scopus, EMBASE/Ovid, Cochrane Library, DARE, LILACS and Pro Quest databases was conducted by three reviewers until 10th January 2024 and then updated on 18th August 2024. Eligibility criteria included peer-reviewed articles published in English, focusing on human teeth, with available full text excluding reviews, conference proceedings and gray literature. The outcomes of interest were the quality of tooth preparation, surface characteristics, bond strength, thermal effects and damage to adjacent tissues with variables being laser parameters and tooth types. Methodological quality of studies was not conducted. The search yielded 48 articles after the removal of duplicates, irrelevant and non-retrievable articles. All were original in vitro studies investigating reporting on the outcomes of interest. Measurement methods included a range of microscopy, spectroscopy, optical coherence tomography, universal force testing and thermal imaging. Sapphire lasers were most commonly used with a wide range of parameters. Laser produced sharp-edged cavities with ablated surfaces free of melting (seen in approximately 10% of the craters), cracking, debris, with open dentinal tubules, increased wetting (Contact angle mean range 39.63 ̊(± 1.84 ̊) to 70.47 ̊(± 10.27 ̊) and roughness mean range 0.82 (± 0.05) to 4.20 (± 1.10)µm). Effects of femtosecond laser on bonding efficiency were inconsistent when compared to no treatment, conventional acid etching or Er:YAG laser. Femtosecond laser was shown to achieve precise tooth preparation with no or minimal thermal, mechanical and structural effects on adjacent tissue, however with variable bonding efficiency. Further research is needed to optimize laser parameters, investigate antibacterial effects, and establish long-term clinical outcomes and safety profiles. Date of registration: July 1st, 2024. Registration ID: OSF.IO/UQMNB. [ABSTRACT FROM AUTHOR]

In this work, a shear stress test is used to evaluate the ice adhesion strength on "as received", polished and micro/nanoengineered hierarchical superhydrophobic aluminium (produced via one-step laser etching) with fixed- and gradient-pitch structures. Due to the potential mismatch between the ice formation area and the wetting gradient length scale, the shear stress test method has been analysed in detail to understand its applicability to topographic gradients, since this could provide misleading results as compared with the application of this method to fixed-pitch topographic structured surfaces. To address this, the influence of the ice-surface contact area, as well as the mould shape and mould material, on the ice adhesion results, was observed for all samples. Moreover, the impact of the direction of the removal force was investigated on the wetting gradients. Key results are that topographically altered surfaces can be hydrophobic, but not icephobic; whereas non-altered surfaces are hydrophilic, but with much lower ice adhesion. Additionally, gradient surfaces were observed to provide hydrophobicity for most areas of the surface, while allowing removal of the ice column at lower forces from certain directions. [ABSTRACT FROM AUTHOR]

In this study, the optimal engraving parameters were determined through the analysis of scanning electron microscopy (SEM) data, as follows: a laser power density of 5.5 × 105 W/cm2, an irradiation rate of 0.1 mm/s, a well radius of 60 μm, a distance between well centers of 200 μm, and a number of passes for each well of 20. After 1 week of in vitro cultivation, chondrocytes were located on the surface of the scaffolds, in the sockets and lacunae of decellularized cartilage. When implanted into animals, both cellular and acellular scaffolds were able to support cartilage in-growth and complete regeneration of the defect without clear boundaries with normal tissue. Nevertheless, the scaffolds populated with cells exhibited superior biocompatibility and were not subject to rejection, in contrast to cell-free constructs. [ABSTRACT FROM AUTHOR]

The intricate nanostructured surface of black silicon (BSi) has advanced photodetector technology by enhancing light absorption. Herein, we delve into the latest advancements in BSi surface modification techniques, specifically focusing on their profound impact on light trapping and resultant photodetector performance improvement. Established methods such as metal-assisted chemical etching, electrochemical etching, reactive ion etching, plasma etching, and laser ablation are comprehensively analyzed, delving into their mechanisms and highlighting their respective advantages and limitations. We also explore the impact of BSi on the emerging applications in silicon (Si)-based photodetectors, showcasing their potential for pushing the boundaries of light-trapping efficiency. Throughout this review, we critically evaluate the trade-offs between fabrication complexity and performance enhancement, providing valuable insights for future development in this rapidly evolving field. This knowledge on the BSi surface modification and its applications in photodetectors can play a crucial role in future implementations to substantially boost light trapping and the performance of Si-based optical detection devices consequently. [ABSTRACT FROM AUTHOR]

The performance of composite-based triboelectric nanogenerators (C–TENGs) was significantly enhanced through laser surface patterning and graphite coating. The laser etching process produced accurate and consistent patterns, increasing surface area and improving charge accumulation. SEM imagery confirmed the structural differences and enhanced surface properties of the laser-etched C–TENGs. Graphite fibers further augmented the contact surface area, enhancing charge accumulation and diffusion. Experimental results demonstrated that the optimized C–TENGs, especially those with line patterns and graphite coating, achieved a maximal 98.87 V open-circuit voltage (VOC) and a 0.10 µA/cm2 short-circuit current density (JSC) under a 20 N external force. Environmental tests revealed a slight decrease in performance with increased humidity, while long-term stability tests indicated consistent performance over three weeks. Practical application tests showed the potential of C–TENGs integrated into wearable devices, generating sufficient energy for low-power applications, thereby highlighting the promise of these devices for sustainable energy solutions. [ABSTRACT FROM AUTHOR]

Due to its exceptional dimensional stability in harsh thermal conditions and excellent mechanical and optical properties, Corning ultralow expansion (ULE®) glass is the material of choice in many high-demanding fields such as aerospace, astronomy, and advanced optics. This material has recently attracted renewed attention with the advent of femtosecond laser technology, with a particular focus on the interaction of ultrafast pulses and the material itself. Phenomena like the formation of self-assembled nanogratings and their thermal stability as well as the darkening of laser-affected zones have then been characterized. This paper presents how to exploit femtosecond selective laser etching (SLE) techniques to manufacture truly three-dimensional components. To demonstrate the micrometer-scale accuracy and repeatability of this process from the mm- to the cm-size range, various devices are designed and fabricated: fiber hole arrays with different hole densities, sizes, orientations, and shapes; and fiber V-groove arrays. Additionally, a mechanical flexural fiber mount is presented as an example of how multiple functionalities can be monolithically integrated into a single piece of glass through SLE technology. An example of a passive alignment substrate for optical components is also shown. SLE technique represents a new advancement in the field of microscale manufacturing, enabling the scalable production of custom-designed ULE® glass structures with unprecedented precision and complexity, paving the way for the miniaturized integration of highly stable components. [ABSTRACT FROM AUTHOR]

Herein, the first photochemical microscale continuous oscillatory baffled reactor, that is, Photo‐μCOBR, was designed and evaluated. Computational fluid dynamics simulations were used to optimize the key structural parameter and operating conditions. Then, the mixing process was simulated and the μCOBR was shown to be more than 23 times faster than the straight channel both under oscillating conditions. Finally, a glass Photo‐μCOBR was fabricated by femtosecond laser internal engraving technology, and the photocatalytic gas–liquid oxidation of dihydroartemisinic acid was performed. A yield of 65.9% was achieved in a residence time of ~120 s and at a gas–liquid flow rate ratio of 1:3 (vs. 18.6% in the capillary photomicroreactor under identical conditions). The results in this work offer guidelines for the design and operation of microscale COBRs, and the as‐fabricated Photo‐μCOBR displays good potential for gas–liquid photochemical reactions. [ABSTRACT FROM AUTHOR]

Multiscale microtextures were fabricated on the surface of TA1 foil using laser etching and laser shock imprinting (LSI) processes. First, laser etching process was employed to directly fabricate multiscale microtextures on the 20 µm thick TA1 foil as the laser etching workpiece. Then, using the same laser etching parameters, multiscale microtextures were processed on a 1 mm thick TA1 plate surface as the mould for LSI. Finally, the LSI was used to replicate similar multiscale microtextures from the mould surface, and the influence of pulse number and power density on the forming depth and replication degree of the TA1 workpiece was analysed. By comparing the aging effect and durability of the hydrophobic TA1 foils treated by laser etching and LSI processes, the differences in chemical composition stability and mechanical stability between laser etching and LSI surfaces were analysed. The laser etching surface exhibited a super-hydrophilic state within 12 hours and tended to be a superhydrophobic state after 30 days of storage in air. In contrast, no obvious aging effect was observed on the surface of the LSI samples, indicating better stability of surface wettability (110°

Sodium hydroxide (NaOH) is increasingly drawing attention as a highly selective etchant for femtosecond laser-modified fused silica. Unprecedented etching contrasts between the irradiated and pristine areas have enabled the fabrication of hollow, high-aspect-ratio structures in the bulk of the material, overcoming the micrometer threshold as the minimum feature size. In this work, we systematically study the effect of NaOH solutions under different etching conditions (etchant concentration, temperature, and etching time) on the tracks created by tightly focused femtosecond laser pulses to assess the best practices for the fabrication of hollow nanostructures in bulk fused silica. [ABSTRACT FROM AUTHOR]

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Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We demonstrate a genuine method for three-dimensional pictorial reconstructions of two-dimensional, three-dimensional, and hybrid specimens based on confocal Raman data collected in a back-scattering geometry of a 532-nm setup. The protocol, or the titular PRISM (Phase-Resolved Imaging Spectroscopic Method), allows for sub-diffractive and material-resolved imaging of the object's constituent material phases. The spacial component comes through either the signal distal attenuation ratio (direct mode) or subtle light-matter interactions, including interference enhancement and light absorption (indirect mode). The phase component is brought about by scrutinizing only selected Raman-active modes. We illustrate the PRISM approach in common real-life examples, including photolithographically structured amorphous Al2O3, reactive-ion-etched homoepitaxial SiC, and Chemical Vapor Deposition graphene transferred from copper foil onto a Si substrate and AlGaN microcolumns. The method is implementable in widespread Raman apparatus and offers a leap in the quality of materials imaging. The lateral resolution of PRISM is stage-limited by step motors to 100 nm. At the same time, the vertical accuracy is estimated at a nanometer scale due to the sensitivity of one of the applied phenomena (interference enhancement) to the physical property of the material (layer thickness). [ABSTRACT FROM AUTHOR]

To evaluate and compare the shear bond strength of composite resin restorations in primary teeth, following cavity preparation with both traditional dental burs and laser irradiation. One hundred primary molars extracted from the children visiting our department were collected and randomly divided into five groups (A-E) with 20 teeth in each group. In groups A, B, C, D, and E the teeth samples were etched with phosphoric acid, Er; YAG laser followed by acid etching, Er, Cr: YSGG laser followed by acid etching, Er; YAG laser etching only and Er, Cr: YSGG laser etching only, respectively. Following, all the samples were restored with composite resin and subjected to 500 cycles of thermocycling. The shear bond strength of the resin composite was analyzed. The type of fractures was also noted. Data obtained were subjected to statistical analysis. The mean value of shear bond strength of Group A, B, C, D, and E was 17.562 ± 0.810, 15.928 ± 0.415, 14.964 ± 0.566, 11.833 ± 0.533 and 11.187 ± 0.517, respectively. Adhesive failure was most commonly seen in all the groups. The phosphoric acid etching remains a highly effective technique for pre-treating dentin in composite resin restorations. The shear strength of composite resin to the dentin of laser-prepared cavity in primary teeth can be improved by the addition of acid etching. [ABSTRACT FROM AUTHOR]

This paper presents an industrial wireless control and monitoring system for laser cutters and engravers based on computer numerical control (CNC), which aims to improve the overall performance, efficiency, and safety of the CNC machine and its peripherals as an ecosystem by allowing users to operate and maintain it remotely using Wi-Fi. The developed system is implemented through a dynamic hardware module and a multi-OS user application, thereby establishing real-time and simplified communication between the operator and the Laser Cutter/Engraver-CNC ecosystem for remote control and monitoring functions. Further, the system allows for configuring machine settings, and the start or stop of cutting or engraving processes. A Laser Cutter/Engraver-CNC ecosystem prototype was built and used in a test-validated environment to confirm the effectiveness of this system design. [ABSTRACT FROM AUTHOR]

Inconel® 718, known for its excellent mechanical properties in extreme conditions, presents machining challenges due to its low machinability. The chip formation process, influenced by its high ductility and low thermal conductivity, leads to material adhesion and high cutting forces. Ceramic tools have been proposed to mitigate these inconveniences. Textured cutting tools have emerged as a promising solution, aiming to optimise tool-chip contact and, with it, the tribological conditions and the cutting forces. This study investigates the influence of textured grooves on ceramic tools when turning Inconel® 718. Two groove inclinations, 0° and − 25° relative to the cutting edge, were tested. Texturing was performed using a laser station. Experimental results showed improved tool wear characteristics with textured tools, indicating favourable chip extraction and reduced material adhesion. Cutting forces were notably lower with textured tools compared to the reference tool, attributed to reduced notch wear and altered chip flow. Chip morphology analysis revealed differences in chip shape and thermal stability between the reference and textured tools. In conclusion, textured tools, particularly those with − 25° inclined grooves, demonstrated enhanced performance in machining Inconel® 718. [ABSTRACT FROM AUTHOR]

Copyright of FME Transactions is the property of University of Belgrade, Faculty of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article presents a low-cost apparatus designed for teaching geometric optics experiments to first-year university students. The apparatus is made of medium-density fiberboard and uses glass optical elements to verify the laws of reflection and refraction. It allows for the direct observation of lateral displacement caused by a rectangular plate and the determination of the refractive index of the plate's material. Additionally, it enables investigation of refraction through a Littrow prism by determining its minimum deviation angle. The apparatus is economic, safe, and easy to use, making it suitable for educational purposes. The authors acknowledge the contributions of the Optics Research Group at Damietta University and Mohamed A. Atwa to the implementation of the apparatus. [Extracted from the article]

Copyright of CULCyT: Cultura Científica y Tecnológica is the property of Cultura Cientifica y Tecnologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study designed laser engraving and resin pre-coating (RPC) treatments on an aluminum alloy (AA) surface to construct through-the-thickness "epoxy pins" for improving the bonding strength with carbon fiber reinforced polymer (CFRP). A laser engraving treatment was used to create a pitted structure on the AA surface; higher wettability was acquired and greater vertical spaces were formed to impregnate epoxy resin, resulting in stronger mechanical interlocking. The RPC technique was further used to guide high-viscosity epoxy resin into pits to form the epoxy coatings and to minimize defects between the resin and the substrate. The bonding strength of the specimen treated with both laser engraving with a unit dimension of 0.3 mm and RPC increased up to 227.1% in comparison with that of the base. The failure modes of the hybrid composites changed from the debonding failure of the AA surface to the delamination-dominated failure of the laminated CFRP composites. It was confirmed that laser engraving is a feasible and effective method when combined with RPC for treating AAs to improve the bonding strength of AA-CFRP composites, which provides a reference for preparing high-performance hybrid composites with metals. [ABSTRACT FROM AUTHOR]

Fused silica with surface structures has potential applications in microfluidic, aerospace and other fields. To fabricate structures with high dimensional accuracy and surface quality is of paramount importance. However, it is indeed a challenge to strike a balance between accuracy and efficiency at the same time. Here, a temporally shaped femtosecond laser Bessel-beam-assisted etching method with dual-control of incubation effect is proposed to achieve this balance. Instead of layer-by-layer ablation continuously with Gaussian pulses, silica is modified discretely by double pulse Bessel beam with one single layer. During the modification process, incubation effect is dual-controlled in single shot process and spatial scanning process to generate even modified region efficiently. Then, the modified region is etched to form designed structures such as microholes, grooves, etc. The proposed method exhibits high efficiency for fabrication of surface structures in fused silica. [ABSTRACT FROM AUTHOR]

Joule heating electrodes (JHEs) are required for thermal actuation systems. A highly stretchable, patternable, and low‐voltage operating JHE based on hybrid layers of silver nanowires and carbon nanotubes are reported. The conductive layers are applied on a locally pre‐strained bistable electroactive polymer (BSEP) membrane to form a wrinkled conductive surface with a low resistance of 300 Ω/sq, and subsequently patterned to a serpentine trace by laser engraving. The resistance of the resulting JHE electrode remains nearly unchanged up to 80−90% area strain. By applying a voltage of 7 − 9 V to the electrode, the temperature of the BSEP membrane increased to ~60 °C, well above the polymer's phase transition temperature of 46 °C, thereby lowering its modulus by a factor of 103. An electronic Braille device based on the JHEs on a BSEP membrane is assembled with a diaphragm chamber. The electrode is patterned into 3 × 2 individually addressable pixels. Through Joule heating of the pixels and local expansion of the BSEP membrane using a pneumatic pressure, the pixels deformed out of the plane by over 0.5 mm to display Braille letters. The Braille content can be refreshed for 20 000 cycles at the same operating voltage. [ABSTRACT FROM AUTHOR]

Urine analysis stands as a critical diagnostic tool, offering insights into health and disease. However, current techniques demand sophisticated equipment or significant sample processing for urine examination, reducing their suitability for regular point‐of‐care assessments. This study introduces a novel multi‐component sensing platform to address these constraints. The proposed sensor array can detect sodium (Na+), potassium (K+), ammonium (NH4+), calcium (Ca++), chloride (Cl−), and pH levels, thus, enabling real‐time urine analysis. This sensing platform utilizes an extended gate (EG)‐field effect transistor (FET) design employing EG electrodes made of LASER engraved graphene on flexible Kapton substrates. These experimental findings from individual sensors demonstrate consistent linear responses to ion levels, discrimination of specific ions among interferences, and operational stability over time. Additionally, the six‐channel sensor array exhibits notable sensitivity and selectivity in a urine environment, effectively discerning various ions and pH, illustrating its efficacy for urine analysis and validating its potential for reliable point‐of‐care diagnostics. [ABSTRACT FROM AUTHOR]

Stretchable pressure sensor arrays are ideal for biomimetic electronic skin (e‐skin). However, conventional pressure sensors exhibit noticeable strain interference when stretched. This article introduces an advanced fabrication method based on dual‐band laser selective etching to create stretchable pressure sensor arrays free from strain interference. An intact sensitive film is sandwiched between the top and bottom electrodes and then etched into separate sensing cells. Silicone gel with an extremely low Young's modulus (0.157 kPa) is employed as the strain buffer layer, filling the space within sensing cells to absorb device strain during stretching. The pressure sensor arrays demonstrate exceptional interference‐free performance, with the resistance of sensing cells remaining unchanged under strains exceeding 20%. Pressure sensor arrays of 32 × 32 units are manufactured, showcasing a resistive response time of ≈40 ms during compression and 20 ms during release, along with a sensitivity of 0.7702 kPa−1 within the range of 1–70 kPa. Finally, the sensor arrays are integrated into a robotic hand as biomimetic e‐skin, coupled with deep learning algorithms, successfully identifying static and dynamic pressure distributions and achieving an average precision rate of over 99% in recognizing 2D shapes and objects. [ABSTRACT FROM AUTHOR]

This study aims to establish and optimize a process for the fabrication of 3D microstructures of the biocompatible polymer Parylene C using hot embossing techniques. The different process parameters such as embossing temperature, embossing force, demolding temperature and speed, and the usage of a release agent were optimized, utilizing adhesive micropillars as a use case. To enhance compatibility with conventional semiconductor fabrication techniques, hot embossing of Parylene C was adapted from conventional stainless steel substrates to silicon chip platforms. Furthermore, this adaptation included an investigation of the effects of the hot embossing process on metal layers embedded in the Parylene C, ensuring compatibility with the ultra-thin Parylene printed circuit board (PCB) demonstrated previously. To evaluate the produced microstructures, a combination of characterization methods was employed, including light microscopy (LM) and scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR). These methods provided comprehensive insights into the morphological, chemical, and structural properties of the embossed Parylene C. Considering the improved results compared to existing patterning techniques for Parylene C like plasma etching or laser ablation, the developed hot embossing approach yields a superior structural integrity, characterized by increased feature resolution and enhanced sidewall smoothness. These advancements render the method particularly suitable for diverse applications, including but not limited to, sensor optical components, adhesive interfaces for medical wearables, and microfluidic systems. [ABSTRACT FROM AUTHOR]

Investigating the optimal laser processing parameters for industrial purposes can be time-consuming. Moreover, an exact analytic model for this purpose has not yet been developed due to the complex mechanisms of laser processing. The main goal of this study was the development of a backpropagation neural network (BPNN) with a grey wolf optimization (GWO) algorithm for the quick and accurate prediction of multi-input laser etching parameters (energy, scanning velocity, and number of exposures) and multioutput surface characteristics (depth and width), as well as to assist engineers by reducing the time and energy require for the optimization process. The Keras application programming interface (API) Python library was used to develop a GWO-BPNN model for predictions of laser etching parameters. The experimental data were obtained by adopting a 30 W laser source. The GWO-BPNN model was trained and validated on experimental data including the laser processing parameters and the etching characterization results. The R2 score, mean absolute error (MAE), and mean squared error (MSE) were examined to evaluate the prediction precision of the model. The results showed that the GWO-BPNN model exhibited excellent accuracy in predicting all properties, with an R2 value higher than 0.90. [ABSTRACT FROM AUTHOR]

A novel five-surface phosphor-in-glass (FS-PiG) structure for high illumination and excellent color uniformity in large-view scale LEDs for sensor light source application is demonstrated. YAG phosphor (Y3Al5O12:Ce3+) was uniformly mixed with ceramic and sintered at 680 °C to form a phosphor wafer. Sophisticated laser engraving was employed on the phosphor wafer to form saddle-shaped large-view scale FS-PiG LEDs. The performance of the FS-PiG LEDs exhibited an illumination of 401 lm, average color temperature (CCT) of 5488 K ± 110 K, and color coordinates (CIE) of (0.3179 ± 0.003, 0.3352 ± 0.003). In contrast to convention single-surface phosphor-in-glass (SS-PiG) LEDs, the performance exhibited an illumination of 380 lm, average CCT of 5830 K ± 758 K, and CIE of (0.3083 ± 0.07, 0.3172 ± 0.07). These indicated that the performance of the FS-PiG LEDs was higher than the SS-PiG LEDs for illumination, CCT, and CIE by 1.7, 7, and 23 times, respectively. Furthermore, the FS-PiG LEDs demonstrate a lower lumen loss of 2% and a reduced chromaticity shift of 5.4 × 10−3 under accelerated aging at 350 °C for 1008 h, owing to the high ceramic melting temperature of up to 510 °C. In this study, the proposed FS-PiG large-view scale LEDs with excellent optical performance and high reliability may be promising candidates to replace the conventional phosphor-in-organic silicone material used in high-power LEDs for the next generation of sensor light sources, display, and headlight applications. [ABSTRACT FROM AUTHOR]