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Microchannel Fabrication in Fused Quartz by Backside Laser-Induced Plasma Ablation Using 248 nm KrF Excimer Laser
摘要： Laser-induced plasma ablation (LIPA) using a 248 nm KrF excimer laser was investigated for microchannel fabrication. Examination of the morphology in relation to ablation performance was emphasized, and a synthetic LIPA mechanism model was proposed based on the results. Backside LIPA with a metal target on the bottom can be attributed to a combination of two phenomena: laser-induced plasma vaporization thermal ablation from the metal target below and enhanced laser–glass direct interaction from the plasma residuum. The laser absorption enhancement of quartz substrate resulting from the metal residuum was validated clearly using absorption spectrum measurements. The influence of laser parameters on the etching quality during LIPA was also analyzed for processing optimization. Finally, fused quartz glass microchannels of outstanding surface quality and dimension uniformity were implemented. The channel depth was 28 μm, and the bottom surface roughness was better than several hundred nanometers.
关键词： excimer laser,plasma,fused quartz glass,laser ablation,microstructure
更新于2025-09-16 10:30:52
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FEM modeling simulation of laser engraving
摘要： In this paper, a 3D simulation model for nanosecond pulsed laser engraving process is developed, using the finite element method (FEM) aiming at the prediction of the final geometry of the workpiece and optimizing the process. A general heat transfer model is adapted where the incidence laser beam causing the material ablation is modeled using a Gaussian surface heat source, taking into account the interaction between the laser beam, the workpiece material, and the generated metal-vapor plasma. To validate the simulation model, a large set of experiments was performed for the purpose of comparing the experimental with the simulation results. The experiments were conducted on stainless steel and a pressure vessel steel plate using the DMG MORI Lasertec 40 machine for various combinations of the three machining process parameters: average power, repetition rate, and scanning speed. The experimental results positively validated the simulation model. Τhe numerical results were examined and some conclusions were drawn about the effect of the machining parameters on the laser engraving process.
关键词： Simulation,Finite elements method,Laser ablation,Laser engraving
更新于2025-09-16 10:30:52
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Dynamics of nanosecond-laser-induced melting of tin in vacuum, air, and water
摘要： Tin with its low melting point and vapor pressure is a good model material to investigate laser ablation mechanisms under various ambient conditions. Here we measured the nanosecond-laser-induced damage thresholds of tin in vacuum, air, and water. The threshold fluence is found to be ~ 0.1 J/cm2 regardless of the environment unlike more refractory metals when threshold values in water are considerably higher than those in air. Analysis of the morphology and chemical composition of the irradiated surface as well as numerical simulations of tin laser heating demonstrate that the observed surface modification is due to melting but not oxidation. For the case of water environment, the conductive heat transfer to water is found to play only a minor role in tin heating and melting. The simulations show also that the formation of a water vapor layer near the tin surface occurs at a considerably higher fluence, above 0.15 J/cm2, and thus the surface damage is not affected by scattering of the incident laser light by the vapor–liquid interface, typical for more refractory metals. Peculiarities of laser ablation of low-melt materials in liquids and nanoparticle formation are discussed.
关键词： Nanosecond laser,Laser ablation,Water vaporization,Nanoparticle formation,Melting,Tin
更新于2025-09-16 10:30:52
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The Study on Tuning Photoluminescence of Colloidal Graphene Quantum Dots Synthesized through Laser Ablation
摘要： We report photoluminescence study of Colloidal Graphene Quantum Dots (GQDs) that synthesized from ablation of rGO solution. The rGO solution was ablated using 800 nm Ti-Sapphire femtosecond laser by varying the synthesize parameters such as laser power and ablation time. We observed that changing laser power 1 Watt to become 1.7 Watt and time ablation 20 minutes to become 60 minutes will alterate the Photoluminescence (PL) curve peak of GQDs. In case of ablation power variation, PL data shows that the PL curve peak excited by 280 nm laser changed from 369.09 nm to 371.02 nm, and when it excited by 290 nm the PL curve peak slightly changed from 388.17 nm to 393.8 nm. The alteration of Photoluminescence peak is also observed in the variation of time ablation experiment, The PL curve peaks from GQDs time ablation variation samples excited by 280 nm were slightly changed from 376.81 nm to 373.59 nm, and when it excited by 290 nm laser, the PL curve peak is 391.55 nm then changed to 392.11. The change of PL peak on laser power or time ablation variation shows that both parameters will alter either the size, shape, or the edge-type of GQDs.
关键词： Laser Ablation,Ti-Sapphire Femtosecond Laser,Graphene Quantum Dots,Photoluminescence,Reduced Graphene Oxide
更新于2025-09-16 10:30:52
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Phenomenological studies of femtosecond laser ablation on optical thin films for integrated photonics
摘要： In this work, we present a well-supported procedure to fabricate ridge optical waveguides onto thin films of PLZT by femtosecond laser ablation. To achieve smooth-guiding structures that guarantee good optical performance we have studied the characteristics of ablation threshold for different kinematic conditions of fs laser machining and we have also explored the different ablation regimens for several fluences reached. Furthermore, we characterized the morphology and roughness of ridge waveguides through a modal analysis of scattering loss for waveguides conducted by single and multiple scans. An innovative phenomenological model that describes the sidewall roughness to process parameters is proposed in this paper. With this approach, it is possible to extend the manufacturing method of smooth-guiding structures to many optical thin films by fs micromachining, so as to create integrated photonics devices that can be addressed to different technological applications.
关键词： Thin films,Integrated photonics,Laser materials processing,Optical waveguides,Femtosecond laser ablation
更新于2025-09-16 10:30:52
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Rapid synthesis of metallic and alloy micro/nanoparticles by laser ablation towards water
摘要： A versatile method named laser ablation towards water (LATW) was developed to rapidly and simply synthesize metallic and alloy micro/nano particles, even high-entropy-alloy nanoparticles (NPs). A nanosecond pulsed laser beam passed through a transparent glass substrate, ablated its coated metallic ?lm in the air or contacting with water, and synthesized a colloidal solution contained the micro/nano particles. In this study, Cu microparticles (MPs, Daverage = 1.8 μm), Cu MPs with Cu2O NPs, Cu2O NPs and Au NPs (Daverage = 9.5 nm) were successfully synthesized by the laser ablation of 10 μm Cu ?lm in the air, 10 μm Cu ?lm in the water, 200 nm Cu ?lm in the water, 200 nm Au ?lm in the water, respectively. The content of bimetallic NPs can be adjusted by the relative thickness ratio of bilayer ?lm using laser ablation. Moreover, the ternary (Au-Ag-Cu), quaternary (Au-Ag-Cu-Pt), and quinary (Au-Ag-Cu-Pt-Ni) alloy NPs were also fabricated by the laser ablation of multilayer metallic ?lm in the water. Therefore, LATW is a ?exible technique for the high-e?ective synthesis of MPs, NPs, and various alloy NPs.
关键词： Laser ablation,Microparticles,Alloy nanoparticles,Nanoparticles,Water
更新于2025-09-16 10:30:52
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Effect of nanostructured metal oxides (CdO, Al2O3, Cu2O) embedded in PVA via Nd:YAG pulsed laser ablation on their optical and structural properties
摘要： The physiochemical properties of Polyvinyl Alcohol (PVA) film was enhanced by embedding with nanostructured metal oxides (CdO, Al2O3, and Cu2O) via one-pot and green method, nanosecond Nd:YAG pulsed laser ablation in liquids technique (PLAL). This process was carried by ablation of metal targets (cadmium, copper, and aluminum) immersed in PVA solution by high intensity pulsed laser in the focusing condition. The enhancing of the PVA properties were appeared by studying the structure, optical and morphology of the prepared films before and after embedding by several technique as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV–Visible, Photoluminescence (PL), Scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). From structural investigation, the XRD patterns showed a reduction of CdO, Al2O3, and Cu2O nanoparticles within PVA chain. From optical investigation, the interaction and the structural modifications occurred between PVA chains and each metal oxide nanoparticles appeared in stretching vibration bands, the optical energy band gap (Eg) values by using Tauc equation equaled to 2.33, 3.63, and 3.54 eV for the oxide of Cd, Al, and Cu, respectively, are a good agreement with previous work, and the Photoluminescence spectra showed decreasing in emission intensity in the case of embedding with metal oxides. From morphological investigation, the FE-SEM images showed a homogeneous distribution with spherical shape of metal oxides through the polymer of PVA. The qualitative and semi-quantitative elemental analysis of the prepared samples via EDX technique confirmed the embedding of the metal oxide in the PVA structure. This work helps to open the route to produce various properties of PVA by embedded with different nanostructured metal oxides.
关键词： Laser ablation,Al2O3,Nd:YAG,Metal oxides,nanosecond,PVA,Nanomaterials,CdO,Cu2O
更新于2025-09-16 10:30:52
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[IEEE 2019 SBFoton International Optics and Photonics Conference (SBFoton IOPC) - Sao Paulo, Brazil (2019.10.7-2019.10.9)] 2019 SBFoton International Optics and Photonics Conference (SBFoton IOPC) - Femtosecond Laser Micromachining for Controlling Surface Wettability
摘要： The use of femtosecond laser to modify the surface of polymeric materials has received great attention in the last decade, due to the possibilities of tailoring the material’s properties yielding technological applications. Here, we report on the microfabrication of an azopolymer by using femtosecond laser pulses, aiming at the control of surface wettability. By properly patterning the polymeric surface structure we were able to increase the surface hydrophilicity, decreasing the water contact angle in about 20 degrees.
关键词： Laser ablation,hydrophilicity,femtosecond micromachining,azopolymer
更新于2025-09-16 10:30:52
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IR‐Laser Ablation of Potassium Cyanide: A Surprisingly Simple Route to Polynitrogen and Polycarbon Species
摘要： Pulsed laser irradiation of solid potassium cyanide (KCN) produces, besides free nitrogen and carbon atoms, the molecular species KN and KC which are potential candidates for interstellar species of potassium. Additionally, N3, N3?, and KC3 are produced and isolated in solid noble gases as well as in solid N2. Molecular potassium nitrene (KN) reacts with dinitrogen in neon and argon matrices after photochemical excitation (λ = 470 nm) forming molecular end-on (C∞v) and side-on (C2v) potassium azide isomers. The side-on isomer (C2v) is thermodynamically favored at the CCSD(T)/ma-def2-TZVP level of theory. It can be obtained from the end-on isomer by UV-irradiation (λ = 273 nm).
关键词： Laser Ablation,Quantum-Chemical Calculations,Polycarbon Compounds,Polynitrogen Compounds,Matrix-Isolation Spectroscopy
更新于2025-09-16 10:30:52
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Ultrafast fabrication of Cu oxide micro/nano-structures via laser ablation to promote oxygen evolution reaction
摘要： Despite the tremendous efforts on the preparation of efficient oxygen evolution reaction (OER) electrocatalysts, it is still a challenge to fabricate stable OER electrocatalysts with good performance on a large scale in a simple, fast, green, and environment-friendly way. Herein, we report a simple way via femtosecond laser ablation to fabricate Cu oxide micro/nano-structures on Cu foams by fine-tuning of the laser parameters. The present method is ultrafast, non-contact, high efficiency, easy control, sustainable, and environment-friendly. The fabricated catalysts exhibit remarkable OER activity and excellent durability in 1 M KOH.
关键词： Water splitting,Laser ablation,Metal oxides,Oxygen evolution reaction
更新于2025-09-16 10:30:52