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Structural variations during aging of the particles synthesized by laser ablation of copper in water
摘要： The formation of particles during ablation of copper (Cu) in distilled water by different pulse duration (5 ns, 200 ps and 30 fs), wavelength (1064 and 355 nm of 5 ns pulses), and energy is demonstrated. It is found that the initial particles of Cu rapidly oxidize to form cupric oxide (CuO) and cuprous oxide (Cu2O) particles. Pulse duration and wavelength play a crucial role during the process of formation, morphology change, and aging of particles. We demonstrate that ultra-short pulses allow obtaining particles with smaller sizes and narrower distribution. It is shown that the morphology of CuO/Cu2O particles in this case becomes more stable.
关键词： wavelength,oxidation,copper,laser ablation,nanoparticles,pulse duration
更新于2025-09-11 14:15:04
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Laser-ablated silicon in the frequency range of 0.1 to 4.7 THz
摘要： The optical performance of high-resistivity silicon with a laser-ablated surface was studied in the transmission mode in the frequency range of 0.1-4.7 THz. A reciprocal relationship between the transmission brightness and the surface roughness was observed at discrete THz frequencies. The measured dispersion was reproduced by the THz wave scattering theory using an effective refractive index model. No significant differences between the samples processed either with ps- or ns-duration laser pulses in ambient air or in argon enriched atmosphere were found in the THz regime. It was demonstrated that the majority of optical losses of the silicon with the laser modified surface were due to the scattering of THz waves and not due to the absorption in silicon-compounds formed during the laser ablation.
关键词： terahertz waves,diffraction,laser-ablation,scattering
更新于2025-09-11 14:15:04
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Optical and structural investigation of synthesis ZnO/Ag Nanoparticles prepared by laser ablation in liquid
摘要： ZnO/Ag nanoparticle was synthesis by using pulsed laser ablation in liquid with various Ag doped at a time of 1, 3, and 5 min. Characterization was carried out with UV–Vis (UV–Visible) Spectrometer, PL 325 (Photoluminescence 325) spectrometer, XRD (X-Ray di?raction), and TEM (transmission electron microscopy). The enhancement of dopant time, the band gap value decrease from 3,021 eV to 2,781 eV and the wavelength peak position was shifted to the red shift which can transform the structure of ZnO nanoparticles and can be applied as food packaging in the future.
关键词： TEM,ZnO/Ag nanoparticles,Laser ablation,Photoluminescence,Band gap
更新于2025-09-11 14:15:04
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One-pot synthesis of nanostructured CdS, CuS, and SnS by pulsed laser ablation in liquid environment and their antimicrobial activity
摘要： We describe here a generic method for producing high-quality metal sulfide nanoparticles of a controllable and narrow size distribution in the nano-metric range. Metal sulfide nanostructures (CdS, CuS, and SnS) are synthesized by using nanosecond pulsed laser ablation in a liquid solution containing sulfur precursor in just one step (one-pot versatile synthesis method). The optical properties have been studied using UV–Visible spectroscopy showing the main characteristic transition peaks of metal sulfides. Transmission electron microscope (TEM) shows a uniform Smaller-sized and nearly spherical nanocrystals exhibited a cross lattice pattern. The structure study by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX) reveal the purity and the spherical crystalline structure of all the prepared nano metal sulfides. After that, the antibacterial activity has been examined against four types of bacteria and unicellular fungi by using agar plate diffusion methods followed by studying the required time for killing. The tested microorganisms strain is showing that CuS nanoparticles have the highest antimicrobial activity.
关键词： Metal sulfides,PLAL,Antimicrobial,Laser ablation,Nanostructure
更新于2025-09-11 14:15:04
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Effects of energy and hydrogen peroxide concentration on structural and optical properties of CuO nanosheets prepared by pulsed laser ablation
摘要： Laser ablation of copper targets using Ce:Nd:YAG laser with pulses of 1064 nm wavelengths at 10 ns pulse width and with different laser pulse energies and in different concentrations of H2O2 solution is investigated experimentally. Cu/CuO flake-like nanostructures with visible band gap and the extension of its light absorption by changing the synthesis parameters such as laser pulse energy and concentration of H2O2 solution were observed. Characterization and comparison of the obtained suspensions are exploited by X-ray diffraction (XRD), UV–vis spectroscopy and field emission scanning electron microscopy (FE-SEM). The XRD analysis data show that in 10 vol% H2O2 solution CuO phase has been synthesized, while with decreasing the H2O2 concentration, Cu phase is also observed. The mean crystallite sizes of CuO were estimated using XRD patterns and were between 2.1 and 3.3 nm. The comparison of the UV–visible absorption spectra indicates that with decreasing pulse energy and decreasing H2O2 concentration up to 5 vol% the band gap of nanoparticles increased from 2.19 eV to 2.34 eV, which is accordant with the quantum confinement effect. FESEM image of all the synthesized samples illustrate the formation of flake-like nanostructure with the thickness of about 12–15 nm.
关键词： Oxides,Nanostructures,Semiconductors,Optical properties,Laser ablation
更新于2025-09-11 14:15:04
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Growth Promotion of Targeted Crystal Face by Nano-Processing via Laser Ablation
摘要： Control of crystal shape is an indispensable step for various applications of crystalline products. However, obtaining the desired crystal shape by conventionally tuning environmental conditions (temperature, additives, etc.) cannot always be reached. Recently, we have developed an innovative approach for spatiotemporal control of crystal growth of proteins and amino acids by locally modifying crystal structure (e.g., formation of screw dislocations) via femtosecond (fs) laser ablation. In this work, to clarify the appropriate laser condition for controlling the shape of single crystals with minimized damage, we first systematically investigated the dependence of pulse duration on laser ablation and crystal growth of L-phenylalanine (L-Phe). By using a laser system with tunable pulse durations from fs to nanosecond (ns), we found fs laser ablation can offer nanometer-sized, sharp etching of which diameter was smaller than the diffraction limit. By utilizing such nano-processing via fs laser ablation for promoting the growth of a targeted crystal face, we successfully demonstrated the preparation of a bulky crystal of L-Phe, which are difficult to be obtained by conventional crystallization methods.
关键词： L-phenylalanine,nano-processing,single crystal growth,crystal shape control,femtosecond laser ablation
更新于2025-09-11 14:15:04
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Single shot laser ablation MC-ICP-MS for depth profile analysis of U isotopes in UO <sub/>2</sub> single crystals
摘要： An analytical procedure for determining the n(235U)/n(238U) amount ratio in consecutive layers of UO2 single crystals was developed and validated. A 25 mm circular shaped laser beam with a fluence of only 0.24 J cm?2 was employed for depth profiling 235U and 238U in UO2 single crystals with U isotopes being detected via MC-ICP-MS. The time-resolved 235U and 238U MC-ICP-MS signals obtained from individual laser shots were processed automatically using software specifically developed for this purpose. Downhole fractionation of the n(235U)/n(238U) amount ratio was excluded by shooting 80 laser pulses on a reference UO2 single crystal of known composition, revealing no measurable change in its U isotopic ratio during depth profiling. A linear relationship between the number of laser shots and the average depth of the laser ablation craters was established using confocal laser scanning profilometry. The ns-laser ablation system produced conical craters whose diameters were shown to increase with the number of laser pulses. The shape and roughness of the craters were studied as a function of both the number of pulses and focusing conditions. Using a dual beam focused ion beam (FIB), high resolution scanning electron microscopy (SEM) micrographs revealed the formation of rectangular “tiles” on the reference UO2 single crystal after as little as five laser shots. The ordered, rectangular structure disappeared progressively with increasing number of laser pulses, while simultaneously a sub-micrometric porosity developed. The depth profiling capabilities of the laser ablation system were applied to two UO2 single crystals produced under different experimental conditions involving solid state isotopic mixing of 235U and 238U in order to characterise U self-diffusion in UO2+x. Both UO2 single crystals featured a n(235U)/n(238U) ratio gradient, containing enriched U at the surface and depleted U in the bulk.
关键词： MC-ICP-MS,UO2 single crystals,depth profile analysis,laser ablation,U isotopes
更新于2025-09-11 14:15:04
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Doping nanoparticles using pulsed laser ablation in a liquid containing the doping agent
摘要： While doping of semiconductors or oxides is crucial for numerous technological applications, its control remains difficult especially when the material is reduced down to the nanometric scale. In this paper, we show that pulsed laser ablation of an undoped solid target in an aqueous solution containing activator ions offers a new way to synthesise doped-nanoparticles. The doping efficiency is evaluated for laser ablation of an undoped Gd2O3 target in aqueous solutions of EuCl3 with molar concentration from 10?5 mol L?1 to 10?3 mol L?1. Thanks to luminescence experiments, we show that the europium ions penetrate the core of the synthesised monoclinic Gd2O3 nanoparticles. We also show that the concentration of the activators in the nanoparticles is proportional to the initial concentration of europium ions in the aqueous solution, and a doping of about 1% ([Eu]/[Gd] atomic ratio) is reached. On the one hand, this work could open new ways for the synthesis of doped nanomaterials. On the other hand, it also raises the question of undesired penetration of impurities in laser-generated nanoparticles in liquids.
关键词： EuCl3,doping,luminescence,pulsed laser ablation,Gd2O3,nanoparticles
更新于2025-09-11 14:15:04
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Crafting Interior Holes on Chemically Strengthened Thin Glass Based on Ultrafast Laser Ablation and Thermo-Shock Crack Propagations
摘要： To prevent glass cracking from external mechanical damages, chemically strengthened glass is usually employed. The cutting of strengthened glass becomes critical due to their residual tensile stress induced in the inner core of the display unit of mobile communication and computational devices. This method integrates picosecond laser ablation with quenching induced thermo-shock for accomplishing such a task. Essential analyses are performed based on fracture mechanics and finite element method to provide the scientific basis of such an approach. Experimental results indicate that with a proper temperature control, the proposed method could achieve successful separations for various enclosed shapes with the associated surface roughness satisfying the requirement.
关键词： thermo-shock,Glass,picosecond laser ablation,Packaging
更新于2025-09-11 14:15:04
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Investigation on plasma characteristics in a laser ablation pulsed plasma thruster by optical emission spectroscopy
摘要： In order to further improve the propulsion performance of pulsed plasma thrusters for space micro propulsion, a novel laser ablation pulsed plasma thruster is proposed, which separated the laser ablation and electromagnetic acceleration. Optical emission spectroscopy is utilized to investigate the plasma characteristics in the thruster. The spectral lines at different times, positions and discharge intensities are experimentally recorded, and the plasma characteristics in the discharge channel are concluded through analyzing the variation of spectral lines. With the discharge energy of 24 J, laser energy of 0.6 J and the use of aluminum propellant, the specific impulse and thrust efficiency reach 6808 s and 70.6%, respectively.
关键词： plasma,optical emission spectroscopy,propulsion performance,laser ablation pulsed plasma thruster
更新于2025-09-11 14:15:04