Does the Subsurface Superheating Effect Really Exist?

1998 ◽  
Vol 526 ◽  
Author(s):  
Valentin Craciun ◽  
Doina Craciun
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser ◽  
Target Material ◽  
Target Surface ◽  
Pulsed Laser Ablation ◽  
Laser Wavelength ◽  
Gas Release ◽  
Actual Mechanism ◽  
Emission Volume ◽  
Modification Of The Surface

AbstractThe existence inside targets during pulsed laser ablation of a sub-surface superheating effect (SSSH) has been predicted by numerical temperature estimations. The experimental evidence has been so far only indirect, based on the modification of the surface morphology caused by the explosive volume boiling induced by the SSSH effect. However, round-shaped micrometer-sized cavities formed by gas release due to volume boiling have been found on several target materials even when the temperature estimations did not predict any SSSH effect. Although the SSSH effect could exist under certain conditions, it seems that it is not a prerequisite for explosive volume boiling which is the actual mechanism responsible for droplets emission. Volume boiling could occur whenever a thick liquid layer, whose temperature is much higher than the equilibrium boiling value is formed and lasts for several tens of nanoseconds on the target surface, a situation usually found when the laser wavelength is poorly absorbed by the target material.

Modeling for Chemical-Etching Enhanced Pulsed Laser Ablation

2019 ◽  
Author(s):  
Xing Zhang ◽  
Bo Mao ◽  
Rebecca Histed ◽  
Yiliang Liao
Keyword(s):  
Laser Ablation ◽  
Chemical Etching ◽  
Pulsed Laser ◽  
Target Material ◽  
Pulsed Laser Ablation ◽  
Ablation Rate ◽  
Temperature Dependent ◽  
Laser Shock Processing ◽  
Active Liquid ◽  
Shock Processing

Abstract Pulsed laser ablation (PLA) under active liquid confinement, also known as chemical etching enhanced pulsed laser ablation (CE-PLA), has emerged as a novel laser processing methodology, which breaks the current major limitation in underwater PLA caused by the breakdown plasma and effectively improves the efficiencies of underwater PLA-based processes, such as laser-assisted nano-/micro-machining and laser shock processing. Despite of experimental efforts, little attention has been paid on CE-PLA process modeling. In this study, an extended two-temperature model is proposed to predict the temporal/spatial evolution of the electron-lattice temperature and the ablation rate in the CE-PLA process. The model is developed with considerations on the temperature-dependent electronic thermal properties and optical properties of the target material. The ablation rate is formulated by incorporating the mutual promotion between ablation and etching processes. The simulation results are validated by the experimental data of CE-PLA of zinc under the liquid confinement of hydrogen peroxide.

Effect of the dynamic absorptance of a metallic target surface on pulsed laser ablation

2006 ◽  
Vol 203 (5) ◽  
pp. 906-918 ◽  
Author(s):  
Li Li ◽  
Duanming Zhang ◽  
Zhihua Li ◽  
Li Guan ◽  
Xinyu Tan ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser ◽  
Target Surface ◽  
Pulsed Laser Ablation ◽  
Metallic Target

Early stages of the growth of BaTiO3 thin films studied by Transmission Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 706-707
Author(s):  
M. Grant Norton ◽  
Gerald R. English ◽  
Christopher Scarfone ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Room Temperature ◽  
High Temperature Superconductors ◽  
Pulsed Laser ◽  
Target Material ◽  
Pulsed Laser Ablation ◽  
Cubic Phase ◽  
Transmission Electron ◽  
Tetragonal Form

Barium titanate (BaTiO3) may be used in a number of thin-film applications in electronic and optoelectronic devices. For these devices the formation of epitactic films of the correct stoichiometry and phase is essential. In particular, the tetragonal form of BaTiO3, which is stable at room temperature, exhibits ferro-, pyro- and piezoelectric properties. It is desirable to form films of the tetragonal phase directly and thus to avoid formation of either amorphous or polycrystalline material or to form material of the non-ferroelectric cubic phase. Recently two techniques, pulsed-laser ablation and reactive evaporation, have been used to form BaTiO3 thin-films. In the present study BaTiO3 thin-films have been formed using the pulsed-laser ablation technique. Pulsed-laser ablation is now widely used to produce thin-films of the high temperature superconductors and has many advantages over other techniques, in particular the formation of films which maintain the stoichiometry of the target material and by controlling the processing conditions the formation of films having defined crystalline phases.

Comparative Study of Bismuth Composites Obtained via Pulsed Laser Ablation in a Liquid and in Air for Photocatalytic Application

2020 ◽  
Vol 312 ◽  
pp. 172-178
Author(s):  
Valery A. Svetlichnyi ◽  
Elena D. Fakhrutdinova ◽  
Tatiana S. Nazarova ◽  
Sergei A. Kulinich ◽  
Olga V. Vodyankina
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Laser Wavelength ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Photocatalytic Application ◽  
Vis Spectroscopy ◽  
Metallic Bismuth ◽  
Synthesized Materials

In the present work, bismuth-based nanoparticles of various compositions were obtained by pulsed laser ablation of a metallic bismuth target in water and air using a Q-switch Nd:YAG laser (wavelength of 1064 nm, pulse duration of 7 ns, frequency of 20 Hz, and pulse energy of 160 mJ). Then the samples were annealed in air at temperatures up to 600°C. A comparative analysis of the obtained powders was carried out using methods of X-ray diffraction, transmission electron microscopy, specific surface area measurements, IR-Fourier and UV-Vis Spectroscopy. The photocatalytic activity of the synthesized materials in the process of Rhodamine B decomposition under irradiation of a LED source (375 nm) was also studied.

scholarly journals Laser wavelength modulated pulsed laser ablation for selective and efficient production of graphene quantum dots

RSC Advances ◽  
2019 ◽  
Vol 9 (24) ◽  
pp. 13658-13663 ◽  
Author(s):  
Sukhyun Kang ◽  
Jeong Ho Ryu ◽  
Byoungsoo Lee ◽  
Kyung Hwan Jung ◽  
Kwang Bo Shim ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Laser Ablation ◽  
Biomedical Applications ◽  
Graphene Quantum Dots ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Laser Wavelength ◽  
Efficient Production ◽  
Laser Ablation In Liquid ◽  
Graphene Oxide Quantum Dots

Graphene quantum dots (GQDs) and graphene oxide quantum dots (GOQDs) can be selectively produced by wavelength-modulated pulsed laser ablation in liquid (PLAL) method, which can used in different applications such as optoelectronic and biomedical applications, respectively.

GROWTH OF TiO2 NANOPARTICLES BY PULSED LASER ABLATION (PLA) IN LIQUID MEDIA AND STUDY OF PHOTOCATALYTIC PROPERTIES

2008 ◽  
Vol 22 (18n19) ◽  
pp. 3193-3200 ◽  
Author(s):  
S. SHADMEHR ◽  
S. M. MAHDAVI ◽  
N. TAGHAVINIA ◽  
A. AZARIAN
Keyword(s):  
Aqueous Solution ◽  
Laser Ablation ◽  
Sodium Dodecyl ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Laser Wavelength ◽  
Titanium Target ◽  
Mean Size ◽  
Uv Visible

We synthesized TiO 2 nanoparticles by pulsed laser ablation of titanium target immersed in an aqueous solution of surfactant sodium dodecyl sulfate (SDS) or deionized water. The surfactant concentration dependence on size of TiO 2 nanoparticles was investigated. The maximum amount of nanoparticles (with mean size of 40 nm in diameter) was obtained in an aqueous solution of 0.001 M SDS. We have also studied the effect of laser wavelength on growth of TiO 2 nanoparticles. UV/visible spectroscopy and Scanning Electron Microscopy observations were employed for characterization of optical properties and particle sizes respectively. As TiO 2 is a famous photocatalyst, we have also done photocatalytic test by Methyl Orange under UV irradiation for prepared samples.

scholarly journals Photoexcitation in thin films deposited on silicon substrates by reactive pulsed laser ablation

2001 ◽  
Vol 3 (4) ◽  
pp. 213-216 ◽  
Author(s):  
A. Giardini Guidoni ◽  
V. Marotta ◽  
S. Orlando ◽  
G. P. Parisi
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Laser Wavelength ◽  
Physical Parameters ◽  
Silicon Substrates ◽  
Halogen Lamp ◽  
Simultaneous Exposure ◽  
Flight Mass Spectrometry

Reactive pulsed laser ablation is a very interesting method to deposit thin films of several materials and compounds such as oxides, nitrides, semiconductors and superconductors. This technique relies on photoablation of pure elements, or a mixture of materials, with simultaneous exposure to a reactive atmosphere. In the case of oxides, reactions between the laser vaporized metals and oxygen lead to the formation of intermediate complexes and finally to oxide thin films. The reactivity of the plume has been already studied by our group in other oxides and nitrides productions and ascertained by Time of Flight Mass Spectrometry measurements [1].Thin films of semiconducting oxides such asIn2O3,SnO2, and multilayers of these two compounds have been deposited by Reactive Pulsed Laser Ablation, with the aim to evaluate the behaviour of such films under variable halogen lamp illumination.Deposition of these thin films has been carried out by a frequency doubled Nd-YAG laser (wavelength = 532 nm) on Silicon (100) substrates. A comparison, among indium oxide, tin oxide, and multilayers of indium and tin oxides, has been performed. The influence of physical parameters, such as substrate temperature and oxygen pressure in the deposition chamber, has been investigated. The deposited films have been characterized by Electric Resistance measurements.

Properties of Silicon Nanoparticles Produced by Picosecond Pulsed Laser Ablation

2000 ◽  
Vol 638 ◽  
Author(s):  
M. H. Wu ◽  
R. Mu ◽  
A. Ueda ◽  
D. O. Henderson
Keyword(s):  
Laser Ablation ◽  
Silicon Nanoparticles ◽  
Pulsed Laser ◽  
Size Variation ◽  
Size Control ◽  
Pulsed Laser Ablation ◽  
Laser Wavelength ◽  
Nanosecond Pulsed Laser ◽  
Experimental Geometry ◽  
Selection Of

AbstractSilicon nanocrystals have been fabricated by picosecond pulsed laser ablation. Size control over the nanocrystals can be achieved by careful selection of experimental geometry, laser fluence, laser wavelength, backing gas pressure and distance from plume center. Measurements of optical absorption and photoluminescence confirm that particle size variation does significantly affect bandgap and emission efficiency. Differences between results published previously for nanosecond pulsed laser ablation will also be discussed.

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