scholarly journals Deep Penetration of UV Radiation into PMMA and Electron Acceleration in Long Plasma Channels Produced by 100 ns KrF Laser Pulses

Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1883
Author(s):  
Vladimir D. Zvorykin ◽  
Sergei V. Arlantsev ◽  
Alexey V. Shutov ◽  
Nikolay N. Ustinovskii ◽  
Polad V. Veliev
Keyword(s):  
Specular Reflection ◽  
Laser Pulses ◽  
Electron Acceleration ◽  
High Energy ◽  
Deep Penetration ◽  
Axial Component ◽  
Axially Symmetric ◽  
Slowing Down ◽  
Krf Laser ◽  
Plasma Corona

Long (~1 mm), narrow (30−40 μm in diameter) corrugated capillary-like channels were produced in the axially symmetric 2D interaction regime of 100 ns KrF laser pulses with polymethylmethacrylate (PMMA) at intensities of up to 5 × 1012 W/cm2. The channels extended from the top of a deep (~1 mm) conical ablative crater and terminated in a 0.5 mm size crown-like pattern. The modeling experiments with preliminary drilled capillaries in PMMA targets and Monte Carlo simulations evidenced that the crown origin might be caused by high-energy (0.1–0.25 MeV) electrons, which are much higher than the electron temperature of the plasma corona ~100 eV. This indicates the presence of an unusual direct electron acceleration regime. Firstly, fast electrons are generated due to laser plasma instabilities favored by a long-length interaction of a narrow-band radiation with plasma in the crater. Then, the electrons are accelerated by an axial component of the electrical field in a plasma-filled corrugated capillary waveguide enhanced by radiation self-focusing and specular reflection at the radial plasma gradient, while channel ripples serve the slowing down of the electromagnetic wave in the phase with electrons.

scholarly journals Relativistic electron acceleration by surface plasma waves excited with high intensity laser pulses

2020 ◽  
Vol 8 ◽  
Author(s):  
X. M. Zhu ◽  
R. Prasad ◽  
M. Swantusch ◽  
B. Aurand ◽  
A. A. Andreev ◽  
...  
Keyword(s):  
Electron Flux ◽  
Incidence Angle ◽  
Laser Pulses ◽  
Electron Acceleration ◽  
High Energy ◽  
Laser Wavelength ◽  
Acceleration Process ◽  
Experimental Conditions ◽  
Preformed Plasma ◽  
Scale Length

The process of high energy electron acceleration along the surface of grating targets (GTs) that were irradiated by a relativistic, high-contrast laser pulse at an intensity $I=2.5\times 10^{20}~\text{W}/\text{cm}^{2}$ was studied. Our experimental results demonstrate that for a GT with a periodicity twice the laser wavelength, the surface electron flux is more intense for a laser incidence angle that is larger compared to the resonance angle predicted by the linear model. An electron beam with a peak charge of ${\sim}2.7~\text{nC}/\text{sr}$ , for electrons with energies ${>}1.5~\text{MeV}$ , was measured. Numerical simulations carried out with parameters similar to the experimental conditions also show an enhanced electron flux at higher incidence angles depending on the preplasma scale length. A theoretical model that includes ponderomotive effects with more realistic initial preplasma conditions suggests that the laser-driven intensity and preformed plasma scale length are important for the acceleration process. The predictions closely match the experimental and computational results.

scholarly journals Concept of generation of extremely compressed high-energy electron bunches in several interfering intense laser pulses with tilted amplitude fronts

2012 ◽  
Vol 31 (1) ◽  
pp. 23-28 ◽  
Author(s):  
V.V. Korobkin ◽  
M.Yu. Romanovskiy ◽  
V.A. Trofimov ◽  
O.B. Shiryaev
Keyword(s):  
Laser Pulses ◽  
High Energy ◽  
Intense Laser ◽  
High Energy Electron ◽  
Speed Of Light ◽  
Electron Bunches ◽  
Newton Equation ◽  
High Energies ◽  
Neutral Gas ◽  
Intense Laser Pulses

AbstractA new concept of generating tight bunches of electrons accelerated to high energies is proposed. The electrons are born via ionization of a low-density neutral gas by laser radiation, and the concept is based on the electrons acceleration in traps arising within the pattern of interference of several relativistically intense laser pulses with amplitude fronts tilted relative to their phase fronts. The traps move with the speed of light and (1) collect electrons; (2) compress them to extremely high density in all dimensions, forming electron bunches; and (3) accelerate the resulting bunches to energies of at least several GeV per electron. The simulations of bunch formation employ the Newton equation with the corresponding Lorentz force.

Characterization of columns grown during KrF laser micromachining of Al2O3–TiC ceramics

2003 ◽  
Vol 18 (5) ◽  
pp. 1123-1130 ◽  
Author(s):  
V. Oliveira ◽  
R. Vilar
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Laser Pulses ◽  
Formation Mechanisms ◽  
X Ray ◽  
Reducing Conditions ◽  
Transmission Electron ◽  
Column Formation ◽  
Krf Laser

This paper aims to contribute to the understanding of column formation mechanisms in Al2O3–TiC ceramics micromachined using excimer lasers. Chemical and structural characterization of columns grown in Al2O3–TiC composite processed with 200 KrF laser pulses at 10 J/cm2 was carried out by scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction analysis. Fully developed columns consist of a core of unprocessed material surrounded by an outer layer of Al2TiO5, formed in oxidizing conditions, and an inner layer, formed in reducing conditions, composed of TiC and Al3Ti or an AlTi solid solution. Possible mechanisms of column formation are discussed.

scholarly journals Imaging at an x-ray absorption edge using free electron laser pulses for interface dynamics in high energy density systems

2017 ◽  
Vol 88 (5) ◽  
pp. 053501 ◽  
Author(s):  
M. A. Beckwith ◽  
S. Jiang ◽  
A. Schropp ◽  
A. Fernandez-Pañella ◽  
H. G. Rinderknecht ◽  
...  
Keyword(s):  
Energy Density ◽  
Absorption Edge ◽  
Free Electron ◽  
Free Electron Laser ◽  
Laser Pulses ◽  
High Energy ◽  
High Energy Density ◽  
Interface Dynamics ◽  
X Ray ◽  
X Ray Absorption

Electron acceleration by tightly focused radially polarized few-cycle laser pulses

2012 ◽  
Vol 21 (2) ◽  
pp. 024101 ◽  
Author(s):  
Jin-Lu Liu ◽  
Zheng-Ming Sheng ◽  
Jun Zheng
Keyword(s):  
Laser Pulses ◽  
Electron Acceleration ◽  
Radially Polarized

Doping and crystallization of amorphous SiGe films with an excimer (KrF) laser

1995 ◽  
Vol 10 (8) ◽  
pp. 1884-1888 ◽  
Author(s):  
S. Krishnan ◽  
M.I. Chaudhry ◽  
S.V. Babu
Keyword(s):  
Silicon Germanium ◽  
Room Temperature ◽  
Laser Pulses ◽  
Laser Exposure ◽  
Silicon Substrates ◽  
A Value ◽  
Crystal Film ◽  
Krf Laser ◽  
Amorphous Silicon Germanium

Amorphous silicon germanium (a-SiGe) films, deposited on silicon substrates at room temperature in a molecular beam epitaxy system, were transformed into a single-crystal film and doped with phosphorus by exposure to KrF laser pulses. Electron channeling patterns showed that laser exposure resulted in crystallization of the undoped a-SiGe films. The SiGe films were doped by laser irradiation, using a phosphorus spin-on-dopant. The sheet resistance of the doped films decreased with increasing numbers of pulses, reaching a value of about ∼ 5 × 104 ohms/□ after 15 pulses. I-V data from mesa-type n-SiGe/p-Si diode devices were used to determine the effect of laser processing on the quality of the SiGe films.

Optical fibre beam delivery of high-energy laser pulses: beam quality preservation and fibre end-preparation

2000 ◽  
Vol 34 (4-6) ◽  
pp. 273-288 ◽  
Author(s):  
A. Kuhn ◽  
I.J. Blewett ◽  
D.P. Hand ◽  
P. French ◽  
M. Richmond ◽  
...  
Keyword(s):  
Optical Fibre ◽  
Beam Quality ◽  
Laser Pulses ◽  
High Energy ◽  
Energy Laser ◽  
High Energy Laser ◽  
Beam Delivery
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