Laser Etching Research Articles

A potential-controlled electrochromic visual biosensor based on distance readout for zearalenone detection

In this work, a potential-controlled electrochromic visual biosensor was developed for detecting zearalenone (ZEN) using a distance readout strategy. The sensor chip includes a square detection area and a folded signal output area created with laser etching technology. The detection area is modified with graphene oxide and ZEN aptamer, while Prussian blue (PB) is electrodeposited onto the signal output channel. When an appropriate voltage is applied, PB in the signal output area is reduced to colorless Prussian white (PW). The target ZEN molecules have the capability to release aptamers from graphene oxide (GO) surface in the detection area, resulting in a subsequent change in the potential of the visual signal output channel. This change determines the length of the channel that changes from blue to colorless, with the color change distance being proportional to the ZEN concentration. Using this distance readout strategy, ZEN detection within the range of 1 ng/mL to 300 ng/mL was achieved, with a detection limit of 0.29 ng/mL.

Femtosecond laser etching C-type fiber optic vernier sensor for seawater temperature and salinity measurements

In this work, we demonstrate a dual C-type fiber optic vernier sensor based on femtosecond laser etching for measuring seawater temperature and salinity. The C-type fibers are etched using femtosecond laser microfabrication technology on hollow-core fibers (HCF), including temperature and salinity cavities. The seawater can fully flow into the salinity cavity as a sensing medium, and the polydimethylsiloxane (PDMS) is filled into the temperature cavity as a sensitizing medium. Combined with the vernier effect, dual parameter high sensitivity simultaneous measurement is achieved. Through simulation and experimental testing, the sensor can achieve high sensitivity measurement of seawater salinity and temperature, with sensitivities of −2.69 nm/‰ and −4.54 nm/℃, respectively. In the stability tests of salinity and temperature, the maximum interference wavelength shifts are 0.52 nm and 0.64 nm, respectively. In the repeated measurement experiment, the maximum deviation of sensitivity for salinity cavity and temperature cavity measurements are 0.03 nm/‰ and 0.18 nm/℃, respectively, indicating that the structure has good measurement stability and repeatability. This sensor has the advantages of strong stability, good repeatability, and low cost, which can be used as a new type of sensor to achieve high-sensitivity detection of seawater parameters.

Durable self-cleaning anti-fog and antireflective micro-nano structures fabricated by laser marker ablation of Si coated glass

This study presents an approach for fabricating super hydrophilic self-cleaning anti-fog micro-nano structures on silicon-coated glass utilizing a laser marking machine. The surface features a periodic microstructure interspersed with irregular nanoparticles, which contribute to its durable superhydrophilicity, maintaining a 0° contact angle for up to one year—the longest duration recorded to date. Moreover, it sustained its anti-fogging and self-cleaning abilities for 467 days, establishing the lengthiest duration for maintaining a 0° contact angle and retaining anti-fogging performance without visible deterioration. The sample also retained excellent anti-fogging and self-cleaning properties even after 43 days of outdoor exposure. Such remarkable performance was attributed not only to surface chemistry and roughness but also to the presence of dense, uniform, and minimally varying microstructures. The unique structure also enhanced the solar spectrum (AM 1.5) weighted average transmission by 3.84 % over control glass in the wavelength range of 400–1100 nm. It holds promising potential for use in automotive rearview mirrors, windows, and solar cells.

Enhanced Wear Resistance of Microstripe-Textured Water-Lubricated Materials Fabricated via Hot Embossing

Water-lubricated material is the fundamental ingredient of a water-lubricated bearing (WLB), of which the friction and wear properties directly affect the working performance and service life of a WLB. We designed a micron-scale stripe texture and fabricated a negative microtexture mold by femtosecond laser etching. The microtextures were fabricated onto the surface of Thordon and polyurethane water-lubricated materials by a precision thermoforming machine. Tribological tests showed that the microstripe texture on water-lubricated materials had lower friction and wear properties than that on pristine surface materials. The results demonstrated that the presence of the microstripe texture effectively improved the friction and anti-wear properties of the water-lubricated materials. This study provides a new idea for the design and preparation of water-lubricated materials with good water-lubricating and anti-wear properties.

Experimental study on the updated optimization method for particle size distribution of lost circulation materials

The use of laboratory methods to simulate the process of plugging slurry sealing the fracture is an efficient and convenient method for Lost Circulation Materials (LCMs) selection and formula design. However, commonly used plugging evaluation devices have defects such as small-scale fractures and low reproducibility. To address these shortcomings, we applied a wellbore-fracture coupling plugging experimental device to simulate the process of plugging slurry extrusion. We processed a large-scale visualized fracture using Plexiglas based on the geometric parameters of the formation fracture, reproduced the undulation characteristics of the fracture surface using laser etching technology, and characterized the three-dimensional morphology characteristics of commonly used calcite, walnut shells, and flake polybutyl ester at the wellsite to carry out experiments on the transportation of LCMs under wellbore-fracture coupling conditions. The results indicate that the discrepancy between laboratory evaluation outcomes and field application practices, as well as the low success rate of single-attempt on-site plugging, can be primarily attributed to mouth sealing. The migration behavior of the LCMs is dictated by its morphological characteristics. A larger disparity among the three-axis diameters leads to increased irregularity in the LCM. Characterization of irregularity yielded the following results: walnut shell exhibits the highest irregularity, followed by flaky polybutene and calcite. Increased irregularity in the LCM corresponds to a heightened risk of mouth sealing. Entry into the fracture can only be guaranteed when the D90/Wf ratios for calcite, flaky polybutene, and walnut shell are less than or equal to 0.56, 0.42, and 0.39, respectively. The methods and findings presented in this study provide a scientific basis for selecting LCMs in fractured formations and explain the reasons for poor loss control and significant repetitive loss in wellsite practice.

Enhanced room temperature CO2 photoreduction on gas-solid interfaces using nanocrystals integrated with ZIF-8 wrapping design

Composites derived from metal-organic frameworks (MOFs) show promise as catalysts for the photocatalytic reduction of CO2. However, their potential is hindered by constraints such as limited light absorption and sluggish electron transfer and separation, impacting the overall efficiency of the photocatalytic process. In this study, TiO2 nanocrystals, modified with Ptx+, underwent laser etching were encapsulated within the traditional MOF-ZIF-8 framework. This enhanced the adsorption capabilities for CO2 reactants and solar light, while also facilitating directed electron transfer and the separation of photogenerated charges. The finely-tuned catalyst demonstrates impressive CH4 selectivity at 9.5 %, with yields of 250. 24 μmol g-1 h-1 for CO and 25.43 μmol g-1 h-1 for CH4, utilizing water as a hole trap and H+ source. This study demonstrates the viability of achieving characteristics related to the separation of photogenerated charges in TiO2 nanocrystals through laser etching and MOF composite catalysts. It offers novel perspectives for designing MOF-based catalysts with enhanced performance in artificial photosynthesis.

An Experimental Parametric Optimisation for Laser Engraving and Texturing to Integrate Zirconia Ceramic Blocks into Stainless Steel Cutlery: A State-of-the-Art Aesthetically Improved Perspective.

Cutlery and flatware designs are an everchanging phenomenon of the manufacturing industry. Worldwide hospitality businesses demand perpetual evolution in terms of aesthetics, designs, patterns, colours, and materials due to customers' demands, modernisation, and fierce competition. To thrive in this competitive market, modern fabrication techniques must be flexible, adoptive, fast, and cost effective. For decades, static designs and trademark patterns were achieved through moulds, limiting production to a single cutlery type per mould. However, with the advent of laser engraving and design systems, the whole business of cutlery production has been revolutionised. This study explores the possibility of creating diverse designs for stainless steel 304 flatware sets without changing the entire production process. The research analyses three key laser process parameters, power, scanning speed, and number of passes, and their impacts on the resulting geometry, depth of cut, surface roughness, and material removed. These parameters are comprehensively studied and analysed for steel and zirconia ceramic. The study details the effects of power, scanning speed, number of passages, and fluence on engraved geometry. Fluence (power*number of passages/scanning speed) positively influences outputs and presents a positive trend. Medium power settings and higher scanning speeds with the maximum number of passages produce high-quality, low-roughness optimised cavities with the ideal geometric accuracy for both materials.

Measurement and optimization of writing light field uniformity in dual-galvanometer laser scanning lithography system

The light field uniformity (LFU) in lithography system is a key factor in defining the resolution across the entire micro/nano structures. In this work, a cost-effective and straightforward method based on the focused laser marking on heat-mode resist is proposed for measuring and optimizing the LFU. The factors affecting the LFU are analyzed from the perspectives of optical system aberrations and mechanical assembly error. Subsequently, marking patterns with special structures are designed based on the properties of the heat-mode resist. By analyzing the marked patterns, the LFU of the system is obtained with uniformity coefficient is 42.24%. After optimization achieved by dynamic laser power adjustment, the uniformity coefficient was notably enhanced to 96.11%. This work provides an effective method for measuring and optimizing the LFU in dual-galvanometer laser scanning lithography system.

Secondary electron emission reduction from boron nitride composite ceramic surfaces by the artificial microstructures and functional coating

Boron nitride-silicon dioxide (BN–SiO2) composite ceramic is a typical Hall thruster wall material, and its secondary electron emission (SEE) property dominates the sheath characteristics inside the thrusters. Lowering the SEE yield (SEY) of the wall surface can remarkably improve the sheath stability of Hall thrusters. To accomplish the SEY reduction for BN–SiO2, artificial surface microstructure and surface coating technologies are employed. The morphology analysis demonstrated the shape and feature sizes of the microstructure could be largely controlled by adjusting the laser etching parameters. Then we realized an increasingly significant SEY reduction for BN–SiO2 as the average aspect ratio of the microhole increases. The microstructures showed a remarkable SEY reduction when the laser power was 10 W and the scanning cycle was 50. In this case, the SEY peak values (δ m) of the two BN–SiO2 samples with mass ratios of 7:3 and 6:4 decrease from 2.62 and 2.38 to 1.55 and 1.46 respectively. For a further SEY reduction, a sputtering process was employed to deposit TiN film on the microstructures. The results showed that the TiN coating of 246 nm thickness reduced the δ m values of the two samples from 1.55 and 1.46 to 0.82 and 0.76, which achieved a notable SEY reduction compared to the original surface. Via simulation work, the SEY reduction achieved by microstructures was theoretically interpreted. Besides, by considering the effect of surface charging, the results of SEY converged to 1 with the irradiation pulse increasing presented. The research demonstrated a remarkable SEY reduction for BN–SiO2 ceramic by constructing surface microstructure and depositing TiN coating, which has application sense for low SEY engineering in specific working scenarios.

Investigating the Application and Impact of Laser Etching Technology in the Fabrication of Solar Cells

The most crucial initial step in the metallization process of electroplating is the local contact openings in dielectric layers. In this article, an ultraviolet picosecond laser (UV‐ps), is used to open the front and back dielectric layer of the precursor of n‐TOPCon solar cells. By changing the laser parameters and spot overlap rate, the surface morphology of laser etching under different conditions is obtained and characterized by optical microscope and scanning electron microscope. The results indicate that there are three separate laser shock zones in the dielectric layer under the action of Gaussian light spot, and the corresponding ablation mechanisms are proposed. The longitudinal distribution of B element is characterized by secondary ion mass spectrometry to explore the effect of laser on its pn junction. In addition, the electrical characterization of lifetime photoluminescence is measured and calibrated using WCT120, and this indicates that the majority of the amorphous silicon is recrystallized when applying a fast firing oven process, and this hence improve the minority carrier lifetime and implied open‐circuit voltage. The laser damage to the emitter at the laser‐ablated regions is investigated using the emitter saturation current density, J0laser extracted by WCT120.

Subjective Nature

Science, thought and art meet within the limits of reality, in how reality is understood and represented.. This is where the art-techne binomial materialises graphics, which in turn facilitate the faithful or fictionalised reproduction of our environment. The vocation of science is to advance explanations of the world through a supposedly objective gaze, and the vocation of art is to broaden this understanding by evoking other sensitive and unexpected perspectives. Given the historical relationship between printmaking and the dissemination of knowledge in all fields and the natural sciences in particular, we would like to present the graphic derivations of a collaborative experience between a printmaking artist-cum-researcher and a researcher in forestry science. The experience: A multidimensional approach to the plant: An art and science project started at the end of 2021 when the author, Antía Iglesias, an art student from the interdisciplinary PhD programme in Creativity, Social Innovation and Sustainability (Universidade de Vigo, Spain) (Fig. 1) collaborated with another student, Marion Boisseaux, a PhD student in Tropical Ecology (Université de Guyane) during a research stay in French Guyana. The two students began a joint project to analyse and represent tropical tree seedling species (that Marion had selected in her DRYER project, which observed the effect of drought due to climate change) using their respective technical, numerical and graphical languages, and to provide multiple representations of the plants. This paper aims to present this common experience through the description and analysis of the process that was followed, from a botanical illustration to obtaining graphic digressions from these plants. We will now focus on the derivations obtained from the digital biomimetic record, laser engraving, and printing experimentation.

Laser-assisted screen-printing of graphene folded reflectarray antenna for millimeter-wave applications

Antennas operating at high frequency bands are sought after for applications in 5G, satellite, radar, and other communication systems. Graphene, a two-dimensional material known for its exceptional conductivity, mechanical strength, and chemical stability, is anticipated to serve as a viable substitute for copper in antenna applications. However, researches on graphene antennas at millimeter-wave and higher frequencies are mainly limited to theory and simulation, due to the fabrication challenges of achieving high-precision graphene patterns. Herein, we present the design and fabrication of a graphene folded reflectarray antenna (FRA) operating at millimeter-wave. The FRA is fabricated using screen-printing of graphene ink on an RT5880 substrate, followed by laser engraving for precise patterning. The main reflector has 918 patch units, and the polarizing grids have line widths and spacings of 100 μm. Measurements demonstrate that the antenna has a realized peak gain of 21.37 dBi at 37.5 GHz. The radiation patterns show a 3 dB beamwidth of 6° and 4° in the E-plane and H-plane respectively, with cross-polarization more than −18 dB. The laser-assisted screen-printing method provides a feasible strategy for the precision manufacture of graphene communication devices.

Nanosecond pulsed laser etching anti-reflective gratings and synchronous laser annealing for performance optimization of Ag/AZO thin films

Nanosecond pulsed laser etching for fabricating anti-reflective gratings and inducing synchronous laser annealing was performed on Ag/AZO films. The optimum grating pitch was determined by performance analyses of laser-etched unidirectional gratings, based on which laser-etched bidirectional gratings were fabricated to further determine the optimum grating tilt angle. The results revealed that with the increase of grating pitch, the grating ridge total-side-area was gradually decreased to cause a gradually weakened anti-reflective effect, but the superimposed heat-affected zones between adjacent grooves became smaller or even disappeared, which brought about different synchronous laser annealing effects. The unidirectional grating-textured film with a medium grating pitch of 200 μm showed the best overall performance under the combined influence from anti-reflective gratings and synchronous laser annealing. For the bidirectional gratings, although increasing the grating tilt angle did not change the grating ridge total-side-area, it would enable the laser energy to be more uniformly distributed on the whole film surface, producing a better synchronous laser annealing effect. The bidirectional grating-textured film with a grating tilt angle of 90° had the best overall performance with the highest FOM value of 2.18 × 10−2 Ω−1 that was ∼3.2 times that of the as-prepared film. The results are instructive for preparing high-performance TCO-based films.

Dynamic wetting performance and resin-flow behavior of two-level selective laser-etched metal surface in resin transfer moulding process of fiber-metal laminates

ABSTRACT 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.

Investigating the Laser engraving on Polymethyl methacrylate sheets and process parameters optimization using GRA technique.

Abstract Polymethyl methacrylate (PMMA) is sound-resistant because it can lessen the transmission of outside sound waves. PMMA is widely used in many applications, such as automotive lighting, electronics and energy, health, sanitation, etc. Laser engraving for PMMA sheet panels with process parameters of good quality is a major problem in the process industry. There is a demand for surface roughness that is affected by the volume of material removal. Therefore, in this work, multi-value response optimization was performed on MRR and surface roughness during laser engraving of PMMA sheets using an optical fiber diode in a dry environment through gray relational analysis. Also, regression models are developed, and their responses are compared for their correlation. The GRA combined with the Taguchi method has proved efficient in the decision-making of multi-responses in a laser engraving environment.

Subtractive manufacturing of polymer-derived ceramic composite thick film sensor based on ultrafast laser etching

Polymer-derived ceramics (PDCs) are increasingly recognized as promising materials for high-temperature thin/thick film sensors (HTTFSs). However, a large linewidth and poor dimensional accuracy have severely restricted the practical application of PDCs HTTFSs. Our study employed a picosecond laser to precisely pattern the polymer-derived ceramic (PDC) thick film while applying no obvious damage to the interface between ceramic and substrate. Through parameters optimization, the laser-affected area was minimized to 6 μm wide, and a minimum feature size of about 30 μm was achieved. Furthermore, 7 rounds of high-temperature tests of the patterned film revealed good temperature-resistance repeatability within a temperature range of up to 800 °C. To demonstrate practical application potential, we successfully fabricated a heat flux sensor, and it exhibited a sensitivity of 1.32 mV/(kW/m2), a response time of 600 ms, and excellent repeatability over a range of 0–75.4 kW/m2. In summary, this paper proposes a novel approach toward miniaturizing the linewidth of the polymer-derived ceramics thick film sensor, showing significant potential for precise measurements in extreme environments.

Toward Synthetic Physical Fingerprint Targets.

Biometric fingerprint identification hinges on the reliability of its sensors; however, calibrating and standardizing these sensors poses significant challenges, particularly in regards to repeatability and data diversity. To tackle these issues, we propose methodologies for fabricating synthetic 3D fingerprint targets, or phantoms, that closely emulate real human fingerprints. These phantoms enable the precise evaluation and validation of fingerprint sensors under controlled and repeatable conditions. Our research employs laser engraving, 3D printing, and CNC machining techniques, utilizing different materials. We assess the phantoms' fidelity to synthetic fingerprint patterns, intra-class variability, and interoperability across different manufacturing methods. The findings demonstrate that a combination of laser engraving or CNC machining with silicone casting produces finger-like phantoms with high accuracy and consistency for rolled fingerprint recordings. For slap recordings, direct laser engraving of flat silicone targets excels, and in the contactless fingerprint sensor setting, 3D printing and silicone filling provide the most favorable attributes. Our work enables a comprehensive, method-independent comparison of various fabrication methodologies, offering a unique perspective on the strengths and weaknesses of each approach. This facilitates a broader understanding of fingerprint recognition system validation and performance assessment.

Fabrication of Perfluoropolyether Microfluidic Devices Using Laser Engraving for Uniform Droplet Production.

A perfluoropolyether (PFPE)-based microfluidic device with cross-junction microchannels was fabricated with the purpose of producing uniform droplets. The microchannels were developed using CO2 laser engraving. PFPE was chosen as the main material because of its excellent solvent resistance. Polyethylene glycol diacrylate (PEGDA) was mixed with PFPE to improve the hydrophilic properties of the inner surface of the microchannels. The microchannels of the polydimethylsiloxane microfluidic device had a blackened and rough surface after laser engraving. By contrast, the inner surface of the microchannels of the PFPE-PEGDA microfluidic device exhibited a smooth surface. The lower power and faster speed of the laser engraving resulted in the development of microchannels with smaller dimensions, less than 30 μm in depth. The PFPE and PFPE-PEGDA microfluidic devices were used to produce uniform water and oil droplets, respectively. We believe that such a PFPE-based microfluidic device with CO2-laser-engraved microchannels can be used as a microfluidic platform for applications in various fields, such as biological and chemical analysis, extraction, and synthesis.

Quality improvement of Nd: YAG laser marked DMC and QR codes on the surface of PBT/glass fiber composites by DOE methodology

Laser technology plays an important role in today’s industrial environment. Laser marking is typically used at the end of the production chain to personalize products and make them traceable to the point of sale. One of the challenges of laser marking is the difficulty of creating contrasts whose reflectivity can cause readability problems for electronic decoding devices on production lines, known as scanners. This problem is related to the wrong choice of marking parameters, which results in waste for companies in terms of production stoppages due to rejection, scrap, and customer complaints. Although these problems are common, this process is increasingly used in the industry. Therefore, there is a gap in studies in this field to optimize the marking parameters in many materials, such as PBT (polybutylene terephthalate). The present work was developed in a final assembly line of instrument clusters for motorcycles, where tests were carried out with different types of laser marking parameters, through the implementation of a factorial DoE, with a specific type of laser and material. The laser-marked codes were analyzed in a laboratory using a verifier to assess quality according to ISO/IEC 29158:2020. It was found that the lower the parameter values, the poorer the quality of the codes. The data were statistically processed, and it was possible to identify the marking parameters that ensured the best quality and process performance for DMC and QR codes.

Large-Scale Fabrication of Customized, Tunable, Ultrathin, and Flexible Metamaterial Absorbers Based on Laser-induced Graphene

Developing various 3D graphene microwave absorbers is a hotspot strategy to address the issue of continuous electromagnetic pollution, but remains great challenges in realizing high-performance microwave absorption capability at thin thickness. Herein, a series of flexible metamaterial absorbers (MAs) composed of periodical laser-induced graphene (LIG) surface, dielectric substrate and metallic ground fabric from top to bottom are fabricated. The LIG meta-surface is customized by means of regulating parameters including laser power density (LPD), laser engraving rate (LER) and input patterns to well balance impedance matching and electromagnetic loss. LIG MAs exhibit minimum reflection loss (RL) of −39.7 dB (with effective absorption bandwidth (EAB) of 5.5 GHz) and maximum EBA of 12.1 GHz (with RL of −18.9 dB) at thickness less than 1.1 mm, and the simulated and experimental results are highly consistent. In addition, radar cross section (RCS) simulation of LIG MA with multi-angles endows its potential for prospective applications in in-orbit satellites electromagnetic protection.