scholarly journals Modification of Aerosol Gold Nanoparticles by Nanosecond Pulsed-Periodic Laser Radiation

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2701
Author(s):  
Kirill Khabarov ◽  
Messan Nouraldeen ◽  
Sergei Tichonov ◽  
Anna Lizunova ◽  
Alexey Efimov ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Laser Radiation ◽  
Gas Flow ◽  
Laser Pulses ◽  
Radiation Absorption ◽  
Sintering Process ◽  
Spherical Nanoparticles ◽  
Shrinkage Curve ◽  
Size Modification ◽  
Pulse Energies

This study investigates the processes of interaction of nanosecond pulsed-periodic laser radiation with the flow of aerosol agglomerates of gold nanoparticles synthesized in a spark discharge. Nanoparticles in a gas flow are spatially separated nano-objects whose interaction with each other and with the walls of an experimental cell was insignificant. Therefore, the energy absorbed by nanoparticles was used only for their own heating with further shape and size modification and on heat transfer to the surrounding gas. In the research, we used laser radiation with wavelengths of 527 and 1053 nm at pulse energies up to 900 µJ and pulse repetition rates up to 500 Hz. The dynamics of changes in the nanoparticles size during their sintering process depending on the laser pulses energy is characterized by an S-shaped shrinkage curve. Complete sintering of the initial agglomerates with their transformation into spherical nanoparticles is achieved by a series of impacting laser pulses. The result of nanoparticles’ laser modification is largely determined by the pulse energy and the efficiency of the nanoparticles’ radiation absorption.

scholarly journals Analytical model for the depth progress of percussion drilling with ultrashort laser pulses

2021 ◽  
Vol 127 (5) ◽  
Author(s):  
Daniel Holder ◽  
Rudolf Weber ◽  
Thomas Graf ◽  
Volkher Onuseit ◽  
David Brinkmeier ◽  
...  
Keyword(s):  
Analytical Model ◽  
Experimental Validation ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Picosecond Pulses ◽  
Hole Depth ◽  
Laser Percussion Drilling ◽  
Pulse Energies ◽  
Ultrashort Laser ◽  
Percussion Drilling

AbstractA simplified analytical model is presented that predicts the depth progress during and the final hole depth obtained by laser percussion drilling in metals with ultrashort laser pulses. The model is based on the assumption that drilled microholes exhibit a conical shape and that the absorbed fluence linearly increases with the depth of the hole. The depth progress is calculated recursively based on the depth changes induced by the successive pulses. The experimental validation confirms the model and its assumptions for percussion drilling in stainless steel with picosecond pulses and different pulse energies.

scholarly journals Sputtering of Neutral Molecules and Molecular Ions From the Adenine Crystal Surface Induced by the UV Picosecond Laser Pulse

1982 ◽  
Vol 1 (1) ◽  
pp. 37-43 ◽  
Author(s):  
V. S. Antonov ◽  
V. S. Letokhov ◽  
Yu. A. Matveyets ◽  
A. N. Shibanov
Keyword(s):  
Laser Radiation ◽  
Kinetic Energy ◽  
Crystal Surface ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Molecular Ions ◽  
Laser Radiation Intensity ◽  
Ion Sputtering ◽  
Absorbed Energy ◽  
Picosecond Laser Pulse

This paper presents the results of observation of sputtering of neutral molecules and ions from the crystal adenine surface induced by fourth-harmonic Nd:YAG laser radiation with a pulse duration of 30 ps. The energy fluence of laser pulses was in the region (1–3) × 10−4 J/cm2. The kinetic energy distribution of the sputtered molecules spreads up to 0.7 eV. The experiment shows that the threshold of adenine molecular ion sputtering is connected with absorbed energy density in upper layers of the crystal surface but not by laser radiation intensity.

GENERATION OF ULTRASHORT ELECTRON BUNCHES IN NANOSTRUCTURES BY FEMTOSECOND LASER PULSES

2007 ◽  
Vol 17 (03) ◽  
pp. 571-576
Author(s):  
A. GLADUN ◽  
V. LEIMAN ◽  
A. ARSENIN ◽  
O. MANNOUN ◽  
V. TARAKANOV
Keyword(s):  
Thin Film ◽  
Laser Radiation ◽  
Femtosecond Laser ◽  
Electric Field ◽  
Surface Plasmon ◽  
Laser Pulses ◽  
Photoelectric Effect ◽  
Femtosecond Laser Pulses ◽  
Electron Bunches ◽  
Internal Photoelectric Effect

We present numerical investigation of anomalous internal photoelectric effect which is realized in thin film (< 100 nm) structures by surface plasmon (SP) excitation and its interaction with primary laser radiation. SP electric field gain and electron temperature in the SP field have been calculated.

Excimer Laser Interaction with Metals

1992 ◽  
Vol 285 ◽  
Author(s):  
W.W. Duley ◽  
G. Kinsman
Keyword(s):  
Experimental Data ◽  
Laser Radiation ◽  
Excimer Laser ◽  
Metal Surfaces ◽  
Laser Pulses ◽  
Radiative Properties ◽  
Uv Laser ◽  
Laser Interaction ◽  
Excimer Laser Radiation

ABSTRACTExcimer laser radiation may be used to process metal surfaces in a variety of novel ways. The simplest of these involves the use of UV laser pulses for ablation. Ablation occurs as the result of both vaporization and hydrodynamical effects. Experimental data related to these processes will be discussed. In addition, it will be shown how specific irradiation regimes can yield metal surfaces with unique radiative properties.

Properties of the surface of structural materials in the area of a barcode formed under the action of laser radiation

2021 ◽  
Vol 1 ◽  
pp. 15-24
Author(s):  
Yu.R. Kolobov ◽  
◽  
A.E. Ligachev ◽  
Keyword(s):  
Laser Radiation ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Structural Materials ◽  
Metal Alloys ◽  
Experimental Investigations ◽  
Structure And Properties ◽  
Surface Layers ◽  
Continuous Laser ◽  
Near Surface

A review of experimental investigations of changes in the structure and properties of the surface and near-surface layers of various materials (steels, metal alloys, ceramics and graphite) in the area of a barcode applied by continuous laser radiation and short (nanosecond) and ultrashort (femto- and picosecond) laser pulses.

Fabrication of Anisotropic Structures on the Surface of Amorphous Silicon by Femtosecond Laser Pulses

2020 ◽  
Vol 312 ◽  
pp. 192-199
Author(s):  
Dmitrii V. Shuleiko ◽  
Mikhail N. Martyshov ◽  
Danila V. Orlov ◽  
Denis E. Presnov ◽  
Stanislav V. Zabotnov ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Femtosecond Laser ◽  
Volume Fraction ◽  
Film Surface ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Surface Structures ◽  
Radiation Polarization ◽  
Direction Parallel ◽  
Nanocrystalline Si

Anisotropic periodic relief in form of ripples was formed on surface of amorphous hydrogenated silicon (a-Si:H) films by femtosecond laser pulses with the wavelength of 1.25 μm. The orientation of the surface structures relative to laser radiation polarization vector depended on the number of laser pulses N acting on the film surface. When N = 30, the structures with 0.88 μm period were formed orthogonal to the laser radiation polarization; at N = 750 the surface structures had period of 1.12 μm and direction parallel to the polarization. The conductivity of the laser-modified a-Si:H films increased by 3 to 4 orders of magnitude, up to 3.8·10–5 (Ω∙cm)–1, due to formation of nanocrystalline Si phase with a volume fraction from 17 to 30%. Anisotropy of the dark conductivity, as well as anisotropy of the photoconductivity spectral dependences was observed in the modified films due to depolarizing influence of periodic microscale relief and uneven distribution of nanocrystalline Si phase within such laser-induced structure.

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