Showing papers on "Fluence published in 2012"
TL;DR: In this paper, the carbon ion beam induced modifications on optical, structural and chemical properties of polyallyl diglycol carbonate (PADC) commercially named as CR-39 and polyethyleneterepthalate (PET) polymer films were then irradiated by 55 MeV C 5+ ion beam at various fluences ranging from 1×10 11 to 1× 10 13 ions/cm 2.
104 citations
TL;DR: It is found that for uncoated and coated fused silica samples, the distribution of precursors nearly flattens at very high fluences, up to 150 J/cm2, providing important constraints on the physical distribution and nature of these precursers.
Abstract: Surface laser damage limits the lifetime of optics for systems guiding high fluence pulses, particularly damage in silica optics used for inertial confinement fusion-class lasers (nanosecond-scale high energy pulses at 355 nm/3.5 eV). The density of damage precursors at low fluence has been measured using large beams (1-3 cm); higher fluences cannot be measured easily since the high density of resulting damage initiation sites results in clustering. We developed automated experiments and analysis that allow us to damage test thousands of sites with small beams (10-30 µm), and automatically image the test sites to determine if laser damage occurred. We developed an analysis method that provides a rigorous connection between these small beam damage test results of damage probability versus laser pulse energy and the large beam damage results of damage precursor densities versus fluence. We find that for uncoated and coated fused silica samples, the distribution of precursors nearly flattens at very high fluences, up to 150 J/cm2, providing important constraints on the physical distribution and nature of these precursors.
85 citations
22 May 2012
TL;DR: In this article, the authors focus on metal (gold) nanoparticles produced by ultra-short laser pulses due to their unique plasmonic properties and perform modeling of ultra short laser interactions with gold target in the presence of a liquid (water).
Abstract: Laser ablation in liquids is now commonly used to produce colloidal nanoparticles (NPs) that have found numerous applications in different areas. In the experiments, NPs of different materials can be rather easily produced by using laser systems with various pulse durations, shape, wavelengths, and fluence. Here, we focus our attention on metal (gold) nanoparticles produced by ultra-short laser pulses due to their unique plasmonic properties. To better understand the mechanisms of the NPs formation, we perform modeling of ultra-short laser interactions with gold target in the presence of a liquid (water). The model is similar to that presented in Ref. [1]. In the model, we vary laser fluence. Simulation results show that for smaller laser fluence, gold target is heated to moderate temperatures, so that metastable melted layer is then fragmented into particles (Fig. 1a). In addition, a shock wave, a void/bubble is formed in front of the target [2], so that the particles are ejected into the bubble. They rapidly reach the bubble's front, and all the ablated material can be found near the border of the bubble by ~ 3-4 ns. For larger laser fluences (Fig. 1b), meta-stable liquid decomposes in the vicinity of the critical point forming liquid-gas mixture. The enhanced ablation creates much higher pressure. The bubble is also formed but is rapidly stopped by the hot liquid-gas phase (at ~3 ns after the pulse). At that time, the ablated material is composed of two zone, liquid-gas and liquid, which are then compressed and pushed back. The bubble collapses as soon as at ~7.5 ns due to strong backpressure from the liquid. As a result of the interaction with the ablated material, the target is re-heated and is melted down to as deep as ~0.5 µm under initial target's surface. Thus, the obtained results demonstrate that in the presence of a liquid, the fragmentation of metastable material leads to the NPs ejection. At moderate fluences, liquid just limits material expansion. At larger fluences, liquid pushes the ablated material back enhancing target's temperature, so that more NPs can later originate from this region.
82 citations
TL;DR: In this article, the authors used the Lee Model code and experimental measurements to provide the basis for reference numbers and the scaling of deuteron beams versus stored energy E0, and the ion number fluence (ions m−2) and energy fluence computed as 2.4−7.8
Abstract: Measurements on plasma focusion beams include various advanced techniques producing a variety of data which has yet to produce benchmark numbers [A Bernard et al., J. Mosc. Phys. Soc. 8, 93-170 (1998)]. This present paper uses the Lee Model code [S Lee, http://www.plasmafocus.net (2012)], integrated with experimental measurements to provide the basis for reference numbers and the scaling of deuteron beams versus stored energy E0. The ion number fluence (ions m−2) and energy fluence (J m−2) computed as 2.4−7.8 × 1020 and 2.2−33 × 106, respectively, are found to be independent of E0 from 0.4 to 486 kJ. Typical inductance machines (33–55 nH) produce 1.2−2 × 1015 ions per kJ carrying 1.3%–4% E0 at mean ion energy 50–205 keV, dropping to 0.6 × 1015 ions per kJ carrying 0.7% E0 for the high inductance INTI PF.
81 citations
TL;DR: In this article, the microstructure of high fluence 2 MeV I2+ irradiated Ti3SiC2 has been studied by grazing incident X-ray diffraction (GIXRD) using synchrotron radiation.
80 citations
TL;DR: It is observed that disintegration of the crystal lattice and ion heating of up to 5 eV occur within tens of femtoseconds, and the threshold fluence for Bragg-peak degradation is smaller and the ion-heating rate is faster than current x-ray-matter interaction models predict.
Abstract: We used photon pulses from an x-ray free-electron laser to study ultrafast x-ray-induced transitions of graphite from solid to liquid and plasma states. This was accomplished by isochoric heating of graphite samples and simultaneous probing via Bragg and diffuse scattering at high time resolution. We observe that disintegration of the crystal lattice and ion heating of up to 5 eV occur within tens of femtoseconds. The threshold fluence for Bragg-peak degradation is smaller and the ion-heating rate is faster than current x-ray-matter interaction models predict.
68 citations
TL;DR: In this article, the angular distribution of ions and atoms emanating from femto and nanosecond laser-produced metal plasmas under similar laser fluence conditions was investigated, and the ion and deposited mass features showed that the femto-and nano-conditional laser-ablated metal targets produced higher kinetic energy and more mass per pulse than ns plumes over all angles.
Abstract: We investigated the angular distribution of ions and atoms emanating from femto- and nanosecond laser-produced metal plasmas under similar laser fluence conditions. For producing plasmas, aluminum targets are ablated in vacuum employing pulses from a Ti:Sapphire ultrafast laser (40 fs, 800 nm) and an Nd:YAG laser (6 ns, 1064 nm). The angular distribution of ion emission as well as the kinetic energy distribution is characterized by a Faraday cup, while a quartz microbalance is used for evaluating deposited mass. The ion and deposited mass features showed that fs laser ablated plasmas produced higher kinetic energy and more mass per pulse than ns plumes over all angles. The ion flux and kinetic energy studies show fs laser plasmas produce narrower angular distribution while ns laser plasmas provide narrower energy distribution.
65 citations
TL;DR: In this article, the authors examined the effect of a continuous range of optical fluence for a fixed number of pulses, showing that the dependence of the area of the crystalline mark upon the fluence is well described by simple algebraic results that provide strong evidence that thermal transport within the sample is one-dimensional (vertical) and that a sharp transition between the amorphous and crystalline states of Ge2Sb2Te5 has been studied by exposure of thin films to series of 60 femtosecond (fs) amplified laser pulses.
Abstract: The phase transition between the amorphous and crystalline states of Ge2Sb2Te5 has been studied by exposure of thin films to series of 60 femtosecond (fs) amplified laser pulses The analysis of microscope images of marks of tens of microns in size provide an opportunity to examine the effect of a continuous range of optical fluence For a fixed number of pulses, the dependence of the area of the crystalline mark upon the fluence is well described by simple algebraic results that provide strong evidence that thermal transport within the sample is one-dimensional (vertical) The crystalline mark area was thus defined by the incident fs laser beam profile rather than by lateral heat diffusion, with a sharp transition between the crystalline and amorphous materials as confirmed from line scans of the microscope images A simplified, one-dimensional model that accounts for optical absorption, thermal transport and thermally activated crystallization provides values of the optical reflectivity and mark area that are in very good quantitative agreement with the experimental data, further justifying the one-dimensional heat flow assumption Typically, for fluences below the damage threshold, the crystalline mark has annular shape, with the fluence at the centre of the irradiated mark being sufficient to induce melting The fluence at the centre of the mark was correlated with the melt depth from the thermal model to correctly predict the observed melt fluence thresholds and to explain the closure and persistence of the annular crystalline marks as functions of laser fluence and pulse number A solid elliptical mark may be obtained for smaller fluences The analysis of marks made by amplified fs pulses present a new and effective means of observing the crystallization dynamics of phase-change material at elevated temperatures near the melting point, which provided estimates of the growth velocity in the range 7-9 m/s Furthermore, finer control over the crystallization process in phase-change media can be obtained by controlling the number of pulses which, along with the laser fluence, can be tailored to any medium stack with relaxed restrictions on the thermal properties of the layers in the stack
61 citations
TL;DR: This work investigates the growth behavior of small damage sites on the exit surface of SiO₂ optics under exposure to tightly controlled laser pulses and demonstrates that the onset of damage growth is not governed by a threshold, but is probabilistic in nature and depends both on the current size of a damage site and the laser fluence to which it is exposed.
Abstract: Growth of laser damage on fused silica optical components depends on several key parameters including laser fluence, wavelength, pulse duration, and site size. Here we investigate the growth behavior of small damage sites on the exit surface of SiO2 optics under exposure to tightly controlled laser pulses. Results demonstrate that the onset of damage growth is not governed by a threshold, but is probabilistic in nature and depends both on the current size of a damage site and the laser fluence to which it is exposed. We also develop models for use in growth prediction. In addition, we show that laser exposure history also influences the behavior of individual sites.
60 citations
TL;DR: The Au/Si eutectic reaction and dewetting process caused by the fast melting and solidification dynamics induced by the nanosecond laser irradiations are investigated as the origin of the formation of core-shell nanoparticles.
Abstract: We demonstrate the possibility of producing Au/SiO(2) core-shell nanoparticles by nanosecond laser irradiation of thin (5 and 20 nm) Au films on Si. The Au/Si eutectic reaction and dewetting process caused by the fast melting and solidification dynamics induced by the nanosecond laser irradiations are investigated as the origin of the formation of core-shell nanoparticles. Using several microscopic techniques (Rutherford backscattering spectrometry, scanning electron microscopy, atomic force microscopy, transmission electron microscopy, and energy filtered transmission electron microscopy) the formation and evolution of the core-shell structures are investigated as a function of the laser fluence in the 500-1500 mJ cm(-2) range for both film thicknesses. In particular, the mean height and diameter and surface density evolution of the core-shell structures are quantified and correlated to the laser fluence and Au film thickness.
58 citations
TL;DR: The evolution of the Raman data with fluence shows an accumulation of isolated point defects without amorphization of the material and a partial recrystallized structure, but only at the lowest fluence, suggesting a strong perturbation of the electronic structure.
Abstract: Single crystals of 4H-SiC were irradiated with swift heavy ions (332 MeV Ti, 106 MeV Pb and 2.7 GeV U) in the electronic energy loss regime. The resulting damage was investigated with UV-visible optical absorption spectroscopy and micro-Raman spectroscopy. The evolution of the Raman data with fluence shows an accumulation of isolated point defects without amorphization of the material and a partial recrystallization of the structure, but only at the lowest fluence. Furthermore, the longitudinal optical phonon-plasmon coupling mode disappears upon irradiation, suggesting a strong perturbation of the electronic structure. This evolution is consistent with the optical bandgap decrease and the Urbach edge broadening that was also previously observed for the irradiation with 4 MeV Au ions.
TL;DR: In this article, the effects of laser focusing and fluence on LIBS analysis of pellets of plant leaves was evaluated using a Q-switched Nd:YAG laser (5 n, 10 Hz, 1064 nm).
15 Mar 2012-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
TL;DR: In this paper, the formation of self-organized subwavelength ripples on Al, Si, CaF 2 and CR-39 induced by 25-fs laser pulses at central wavelength of 800nm has been observed under certain experimental conditions.
Abstract: The formation of self-organized subwavelength ripples on Al, Si, CaF 2 and CR-39 induced by 25 fs laser pulses at central wavelength of 800 nm has been observed under certain experimental conditions. In case of Al subwavelength gratings with periodicities ranging from 20 to 220 nm are reported. For CaF 2 the periodicity goes up to 625 nm. In case of Si, nano-gratings have the periodicity of 10–100 nm. The interspacing of these gratings is 60 nm in case of CR-39. These features which are significantly shorter than incident laser wavelength are observed at the irradiation fluence slightly higher than the ablation threshold regardless of the target material. In addition to these nanoripples, classical or microripples with an average spacing of 1–2 μm have also been registered on irradiated surfaces of Al and Si. These microripples have appeared at fluence higher than that is required for nanoripple-formation. It has been found that the formation of the laser-induced ripples is strongly dependent and quite sensitive to the incident laser fluence and the selection of material.
TL;DR: In this article, the optical limiting properties of gold, silver and gold?silver alloy nanoparticles in methyl 2-methylprop-2-enoate for nanosecond laser pulses are presented.
Abstract: The near- and off-resonant optical limiting properties of gold, silver and gold?silver alloy nanoparticles in methyl 2-methylprop-2-enoate for nanosecond laser pulses are presented. The nanoparticles are generated by picosecond pulsed laser ablation in liquid having hydrodynamic diameters from 26 to 30?nm. We use a Q-switched Nd:YAG laser working at a wavelength of 1064 or 532?nm, with a pulse width of 3?ns to characterize their behaviour by laser energy and fluence dependent transmittance measurements. To elucidate the contribution of nonlinear scattering to the optical limiting properties the scattered light energy at an angle of 90??is measured. The experimental results show that these nanoparticles have a strong nonlinear attenuation which can be attributed to intraband, interband and free carrier absorption and a thermal-induced scattering only at high input energies. Our results indicate in addition that the surface plasmon resonance does not contribute to the nonlinear processes at high input energies.
TL;DR: In this paper, the authors employed theory and experiments to investigate the laser ablation process of a metal (Al) using nanosecond laser-pulses at 532 nm wavelength in atmospheric air.
Abstract: Here, we employ theory and experiments to investigate the laser ablation process of a metal (Al) using nanosecond laser-pulses at 532 nm wavelength in atmospheric air. We analyze experimentally the dependence of the ablation rate of Al on laser fluence which is varied over a wide range (from ∼4 to 500 J/cm2) by changing the laser pulses energy. The experimental data indicate that the ablation rate increases approximately linearly to ∼1.5 μm/pulse when increasing the fluence to ∼50 J/cm2, whereas further increase of the laser fluence leads to a much slower, non-linear increase of the ablation rate. By extrapolating towards zero the linear fitting curve, we find the ablation threshold fluence of Al to be ∼1.9 J/cm2. To understand and control the underlying phenomena involved in laser ablation, we propose a robust and efficient theoretical model for reliable yet fast calculation of the ablation rate of metals. We use a one-dimensional photo-thermo-hydrodynamic model that accounts for the material heating, melting, evaporation, melt ejection, and ablation plasma shielding during nanosecond laser irradiation. The model considers that the reflectivity of the target surface, the heat capacity, thermal conductivity, and the mass density of the metallic material depend on the aggregation state. The non-linear heat equation of the model is solved numerically in a multi-step iterative method. The solution of the heat equation gives the time evolution of the temperature within the target, leading further to the evaporation and melt ejection velocities, and to the ablation rate. There is a good agreement between the numerical and the experimental results on the ablation rate for a very wide fluence range, i.e., up to 150 J/cm2 when phase separation occurs in the ablating layer whose average temperature during the laser pulse reaches the Al critical temperature. The validity fluence range of the present model is approximately one order of magnitude wider than in previous theoretical works on nanosecond laser ablation of metals.
TL;DR: In this article, it has been found that adding 10% helium ions into the D plasma at exposure temperatures of 440-650 K significantly reduces the D concentration at depths of 0.5-6μm compared to that for the pure plasma exposure; and generation of the W-ion-induced displacement damage significantly increases the D concentrations at depths up to 2μm (i.e., in the damage zone).
TL;DR: In this paper, the effect of nanosecond laser irradiations on 5 nm thick sputter-deposited Au and Ag films on Indium-TinOxide surface is investigated by atomic force microscopy (AFM) and scanning electron microscopy.
Abstract: The effect of nanosecond laser irradiations on 5 nm thick sputter-deposited Au and Ag films on Indium-TinOxide surface is investigated by atomic force microscopy (AFM) and scanning electron microscopy (SEM). After 500, 750, and 1000 mJ/cm 2 fluence irradiations, the breakup of the Au and Ag films into nanoscale islands is observed as a consequence of fast melting and solidification processes. The mean nanoparticles size and surface density are quantified, as a function of the laser fluence, by the AFM and SEM analyses. In particular, the comparison between the Au and Ag islands reveals the formation of larger islands in the case of Ag for each fixed fluence. The mechanism of the nanoscale islands formation is discussed, both for Au and Ag, in terms of the starting film thickness fluctuations (influencing the local threshold for melting), dewetting phenomenon and the Rayleigh criterion.
TL;DR: In this article, the atomistic model of ablation is developed which reveals that the low threshold fluence of this process is due to the build-up of the high electron pressure and the comparatively low electron-ion energy relaxation rate in gold.
Abstract: We show experimentally the possibility of nanostructuring (about 20 nm) of gold surface by picosecond soft x-ray single pulse with low fluence of ∼20 mJ/cm2. The nanometer-scale changes of the surface structure are due to the splash of molten gold under fluence gradient of the laser beam. In addition, the ablation process occurs at slightly higher fluence of ∼50 mJ/cm2. The atomistic model of ablation is developed which reveals that the low threshold fluence of this process is due to the build-up of the high electron pressure and the comparatively low electron-ion energy relaxation rate in gold. The calculated ablation depths as a function of the irradiation fluence are in good agreement with the experimental data measured for gold surface modification with ultra-short duration soft x-ray and visible lasers.
01 Mar 2012-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
TL;DR: In this article, the degradation induced by MeV He+ ions onto polyethylene terephthalate (PET) is investigated as a function of fluence and electronic stopping power (dE/dx)e.
Abstract: The degradation induced by MeV He+ ions onto polyethylene terephthalate (PET) is investigated as a function of fluence and electronic stopping power (dE/dx)e. Stack samples of four 3.6 μm PET films are irradiated by 3.5 MeV He+ under vacuum and room temperature at fluence ranging from 1013 to 1.5 × 1015 He+ cm−2. The entrance energies range from 3.5 MeV for the front film to 0.573 MeV for the rear one at the beginning of the irradiation and the corresponding mean (dE/dx)e lie for pristine PET between 158 and 264 keV/μm. A Fourier transform infrared spectroscopy (FTIR) analysis is undertaken. The different stack films present similar damages with magnitude increase as the fluence goes up. Moreover, higher is the electronic stopping power (dE/dx)e more important is the damage. The evolution of the normalized integrated absorbance A( ϕ )/A0 of the internal reference 1410 cm−1 band as a function of the fluence ϕ presents a complex behavior characterized by a two-exponential decay associated to low and high fluence range. The analysis reveals clearly that the A( ϕ )/A0 of the characteristic benzene ring 1577 cm−1 band remains steady till fluence around 3 × 1014 He+ cm−2 and then decreases smoothly as fluence increases. The band appearing at 1610 cm−1, assigned to mono substituted benzene, presents an integrated absorbance A( ϕ ) which rises progressively and levels off beyond a critical fluence around 4 × 1014 He+ cm–2. The cross section of the creation of the monosubstituted benzene lies between 3 × 10−15 and 6 × 10−15 cm2 for (dE/dx)e = 158 and 264 keV/μm, respectively. Drastic loss of crystallinity is induced by the MeV He+ ion irradiation in the polymer. The amorphization is monitored by the evolution of the specific bands of the trans and gauche ethylene glycol residue conformations. A sudden drop in the integrated absorbance of the 1340 cm−1 band which characterizes the trans conformation is observed at fluence around 2 × 1014 He+ cm−2. On the other hand, a drastic increase is present in the integrated absorbance of the gauche conformation 1370 cm−1 band that pairs up with 1340 cm−1 band. This observation is a clear indication of the conversion of the trans ethylene glycol residue to gauche one under irradiation.
TL;DR: In this article, the authors used spatially and temporally resolved pump-probe spectroscopy to study the carrier dynamics in single-layer graphene grown by chemical vapor deposition (CVD) by measuring both differential transmission and differential reflection.
Abstract: Carrier dynamics in single-layer graphene grown by chemical vapor deposition (CVD) is studied using spatially and temporally resolved pump-probe spectroscopy by measuring both differential transmission and differential reflection. By studying the expansion of a Gaussian spatial profile of carriers excited by a 1500-nm pump pulse with a 1761-nm probe pulse, we observe a diffusion of hot carriers of 5500 square centimeter per second. We also observe that the expansion of the carrier density profile decreases to a slow rate within 1 ps, which is unexpected. Furthermore, by using an 810-nm probe pulse we observe that both the differential transmission and reflection change signs, but also that this sign change can be permanently removed by exposure of the graphene to femtosecond laser pulses of relatively high fluence. This indicates that the differential transmission and reflection at later times may not be directly caused by carriers, but may be from some residue material from the sample fabrication or transfer process.
15 Sep 2012-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
TL;DR: In this paper, the effect of irradiation parameters such as energy and ions fluence on optical, structural and chemical properties of the studied polymer, respectively, were investigated, and the results can be correlated on the basis of linear energy transfer of the irradiated ions.
Abstract: Makrofol-KG polycarbonate (M-KG PC) films are irradiated with 150 MeV Ni 11+ and 100 MeV O 7+ ion beams at various fluences ranging from 1 × 10 11 to 3 × 10 12 ions/cm 2 . We have investigated the effect of irradiation parameters such as energy and ions fluence on optical, structural and chemical properties of the studied polymer, respectively. UV–Visible, Fourier Transform Infrared (FTIR) and X-ray diffraction (XRD) spectral studies have been employed in the present investigation. UV–Visible spectra exhibit a shift towards the higher wavelength regime after irradiation. This shift clearly reflects decrease in optical band gap after irradiation. The FTIR spectrum shows a decrease in intensity of the typical bands whereas the formation of new bands indicates the degradation of the polymer after irradiation. The XRD pattern of M-KG PC shows the decreasing intensity of peak positions with increase in ions fluence, which suggests loss of crystallinity of the films due to irradiation. Observed results indicate the formation of disordered system in the irradiated films. Magnitude of effect of irradiation is greater in case of 150 MeV Ni 11+ rather than 100 MeV O 7+ ions due to high electronic energy loss of Ni 11+ ions in M-KG PC. The results can be correlated on the basis of linear energy transfer (LET) of the irradiated ions.
TL;DR: In this paper, a process to fabricate arbitrary-shaped, three-dimensional microstructures using focused high-energy proton beam irradiation, followed by electrochemical anodization was developed.
Abstract: We have developed a process to fabricate arbitrary-shaped, three-dimensional microstructures in 04 Ω cm p-type silicon using focused high-energy proton beam irradiation, followed by electrochemical anodization This has enabled us to produce free-standing complex microstructures such as arrays or long wires, grids, wheels, vertically stacked wires and wires which can be controllably bent upward and downward in the vertical plane The two most important factors which determine the wire cross-section dimensions and depth are the irradiation ion fluence and energy We can controllably vary the width of wires from 1 to 5 µm by varying the fluence of 1 MeV protons and the depth of wires from 2 to 15 µm by varying the proton energy By using a combination of multiple energy proton irradiation over a range of 200–1000 keV, and gray-scale masks, different ion penetration depths and multilevel free-standing three-dimensional silicon structures can be obtained in a single etch step
TL;DR: In this paper, the effects of fluid properties and laser fluence on the jet formation process using time resolved imaging analysis during LIFT of glycerol solutions were investigated and it was found that if the fluence is too low and/or the glycerols concentration is too high, it is less likely for a bubble to fully form and/ or grow before it diminishes.
Abstract: Laser-induced forward transfer (LIFT) has been widely studied to print various structures. It is important to investigate the jet and droplet formation process under different LIFT operating conditions. The resulting knowledge will help to better control the resulting printing quality and feature resolution. This study aims to better understand the effects of fluid properties and laser fluence on the jet formation process using time resolved imaging analysis during LIFT of glycerol solutions. It is found that if the laser fluence is too low and/or the glycerol concentration is too high, it is less likely for a bubble to fully form and/or grow before it diminishes. If the laser fluence is too high and/or the glycerol concentration is too low, it is also difficult to form a well-developed jet since dramatic bubble expansion may lead to a bulgy shape and even splashing. Only under certain combinations of glycerol concentration and laser fluence, can a well-defined jet form. When a jetting fluid is given, its...
TL;DR: In this article, a 1,064 nm Nd:YAG laser ablation of solid copper target in water medium was performed using high-resolution transmission electron microscopes (HRTEM).
Abstract: Copper (Cu) nanoparticles of average sizes (radius in nm) varying between 1.7 and 6 nm have been prepared by 1,064 nm Nd:YAG laser ablation of solid copper target in water medium. The nanostructures of the samples have been characterized using high-resolution transmission electron microscopes (HRTEM). The UV–visible absorption spectra obtained with a UV–visible spectrophotometer show sharp absorptions in the ultraviolet region and visible region due to the interband transition and surface plasmon resonance (SPR) oscillations in Cu nanoparticles, respectively. The increase in the linewidth of the SPR absorption peaks with the reduction in particle sizes are observed due to the intrinsic size effects. The behaviour of the UV–visible spectra associated with the Cu nanoparticles is studied as a function of laser fluence and laser ablation time.
TL;DR: In this paper, the effect of laser fluence and an ambient environment on the formation and development of the micro and nano-structures on the laser irradiated stainless steel (AISI-304) targets have been investigated.
TL;DR: In this article, single-wall carbon nanotubes (SWCNTs) functionalized with oxygen-containing groups were deposited onto glass substrates by matrix assisted pulsed laser evaporation (MAPLE).
TL;DR: In this paper, the nanostructuring effects of nanosecond laser irradiations on 5-nm thick Au film sputter-deposited on Si were studied and the formation of Au nanoparticles was observed.
TL;DR: In this paper, the authors report an evolution of surface morphology of silver film irradiated by a 1 kHz femtosecond laser and perform a quantitative analysis of laser fluence and pulse number.
Abstract: In this paper, we report an evolution of surface morphology of silver film irradiated by a 1 kHz femtosecond laser. By SEM observations, it is noted that different nanostructures with respective surface features depend highly on the number of pulses and the laser fluence. Especially when the laser fluence is below the threshold fluence of film breakdown, a textured nanostructure including many nanobumps and nanocavities will appear on the surface of silver film. In order to determine an optimal regime for nanostructuring silver film and to further study the underlying mechanism, we perform a quantitative analysis of laser fluence and pulse number. The results show that this nanostructure formation should be due to a sequential process of laser melting, vapor bubbles bursting, heat stress confinement, and subsequent material redistribution. As a potential application, we find this nanostructured silver film can be used as the active substrate for surface enhanced Raman scattering effect.
TL;DR: In this article, damage evolution of yttria-stabilized zirconia (YSZ) induced by irradiation of 100 keV He ions at room temperature as a function of fluence was investigated.
TL;DR: In this article, the interaction of a TEA CO2 laser, operating at 10.6μm wavelength and pulse duration of 100 ns (FWHM), with a titanium implant in various gas atmospheres was studied.