Heterogeneous Nucleation of Spatially Coherent Damage Structures in Crystalline Silicon with Picosedcond 1.06 μm and 0.53 μm Laser Pulses

1980 ◽  
Vol 1 ◽  
Author(s):  
R.M. Walser ◽  
M.F. Becker ◽  
J.G. Ambrose ◽  
D.Y. Sheng
Keyword(s):  
Electric Field ◽  
Heterogeneous Nucleation ◽  
Crystallographic Orientation ◽  
Free Space ◽  
Crystalline Silicon ◽  
Laser Pulses ◽  
Laser Wavelength ◽  
Beam Spot ◽  
Polarized Beams ◽  
Linearly Polarized

Several types of periodic ripple structures have been observed on the surface of solids that have been laser irradiated with beam intensities near their melting thresholds.1-7 We restrict our attention here to the coherent, onedimensional (RD) gratings induced by linearly polarized beams.3-7 These gratings have a period close to the free space laser wavelength (λ0) for normally incident beams and are normally found in the beam spot near the melt boundary (Fig. 1). The grating lines are always perpendicular to the optical electric field Ei independent of the crystallographic orientation of the sample.

Heterogeneous nucleation of damage in crystalline silicon with picosecond 1.06‐μm laser pulses

1981 ◽  
Vol 39 (1) ◽  
pp. 99-101 ◽  
Author(s):  
D. Y. Sheng ◽  
R. M. Walser ◽  
M. F. Becker ◽  
J. G. Ambrose
Keyword(s):  
Heterogeneous Nucleation ◽  
Crystalline Silicon ◽  
Laser Pulses

scholarly journals Super-hard coatings deposited under conditions of the dynamic shock wave and measurement features of control parameters during production

2020 ◽  
Vol 29 (1) ◽  
pp. 169-176
Author(s):  
Oleg Kuzmin
Keyword(s):  
Laser Beam ◽  
High Speed ◽  
Laser Annealing ◽  
Chemical Properties ◽  
Laser Pulses ◽  
Laser Wavelength ◽  
Femtosecond Laser Pulses ◽  
Hard Coatings ◽  
Linearly Polarized ◽  
Physical And Chemical

AbstractSuper-hard coatings are of increasing scientific interest as they allow synthesizing materials with unique physical and chemical properties for further application in the industry at high-speed processing or tooling. This study is aimed to investigate tetrahedral amorphous carbon (ta-C) films, as well as the dependence of the pulsation parameters on the irradiation parameters and the potential of such pulsations to be further applied in practice. The article shows that ta-C films are completely amorphous and have up to 85% of sp3 bonds. Deposited films are characterized by high compression stresses ranging within 8-10 GPa. The possibilities of reducing these stresses by thermal and pulsed laser annealing have been examined. The formation of ripples in super-hard ta-C films were studied by applying femtosecond laser pulses with a wavelength of 775 nm, an average wavelength of 387 nm, and the pulse duration of 150 fs. Obtained results demonstrated that the orientation of the pulsations on smooth surfaces is perpendicular to the vector of the electric field of the linearly polarized laser beam. Besides, the period of pulsation reduces with decreasing the laser wavelength and/or increasing the angle of laser beam incidence on the substrate.

Laser-Induced Formation of Periodic Structures in Plasma Deposited Polymer Films Containing Au, Ag, and Cu Nanoparticles

2006 ◽  
Vol 960 ◽  
Author(s):  
Katrin Loeschner ◽  
Andreas Kiesow ◽  
Andreas Heilmann
Keyword(s):  
Polymer Films ◽  
Periodic Structures ◽  
Laser Pulses ◽  
Laser Wavelength ◽  
Femtosecond Laser Pulses ◽  
Transmission Electron ◽  
Thin Polymer ◽  
Gold Silver ◽  
Linearly Polarized ◽  
Structure Period

ABSTRACTThin polymer films containing metal nanoparticles were irradiated with linearly polarized femtosecond laser pulses. The resulting laser-induced periodic modification of the nanoparticle assemblies was studied by using scanning and transmission electron microscopy. The structure period Lambda is correlated with the applied laser wavelength lambda by Lambda = 0.7 lambda. The effect was observed for gold, silver and copper nanoparticles. Optical spectra of the laser-irradiated films show a clear dichroism.

Electric field probing by picosecond laser pulses

1992 ◽  
Vol 28 (12) ◽  
pp. 1137 ◽  
Author(s):  
A. Krotkus ◽  
V. Pašiškevičius
Keyword(s):  
Electric Field ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Picosecond Laser Pulses

scholarly journals Cylindrically and non-cylindrically symmetric expansion dynamics of tin microdroplets after ultrashort laser pulse impact

2021 ◽  
Vol 127 (2) ◽  
Author(s):  
Tiago de Faria Pinto ◽  
Jan Mathijssen ◽  
Randy Meijer ◽  
Hao Zhang ◽  
Alex Bayerle ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Droplet Deformation ◽  
Cylindrically Symmetric ◽  
Linearly Polarized ◽  
Particle Hydrodynamics ◽  
Deformation Dynamics ◽  
Smoothed Particle ◽  
Asymmetric Shock

AbstractIn this work, the expansion dynamics of liquid tin micro-droplets irradiated by femtosecond laser pulses were investigated. The effects of laser pulse duration, energy, and polarization on ablation, cavitation, and spallation dynamics were studied using laser pulse durations ranging from 220 fs to 10 ps, with energies ranging from 1 to 5 mJ, for micro-droplets with an initial radius of 15 and 23 $$\upmu$$ μ m. Using linearly polarized laser pulses, cylindrically asymmetric shock waves were produced, leading to novel non-symmetric target shapes, the asymmetry of which was studied as a function of laser pulse parameters and droplet size. A good qualitative agreement was obtained between smoothed-particle hydrodynamics simulations and high-resolution stroboscopic experimental data of the droplet deformation dynamics.

Coherent Ring Currents in Chiral Aromatic Molecules Induced by Linearly Polarized UV Laser Pulses

2013 ◽  
Vol 543 ◽  
pp. 381-384 ◽  
Author(s):  
Manabu Kanno ◽  
Hirohiko Koho ◽  
Hirobumi Mineo ◽  
Sheng Hsien Lin ◽  
Yuichi Fujimura
Keyword(s):  
Aromatic Ring ◽  
Quantum Dynamics ◽  
Ring Current ◽  
Molecular System ◽  
Laser Pulses ◽  
Uv Laser ◽  
Aromatic Molecules ◽  
Ring Currents ◽  
Linearly Polarized ◽  
Coherent Ring

In recent years, laser control of electrons in molecular system and condensed matter has attracted considerable attention with rapid progress in laser science and technology [. In particular, control of π-electron rotation in photo-induced chiral aromatic molecules has potential utility to the next-generation ultrafast switching devices. In this paper, we present a fundamental principle of generation of ultrafast coherent ring currents and the control in photo-induced aromatic molecules. This is based on quantum dynamics simulations of π-electron rotations and preparation of unidirectional angular momentum by ultrashort UV laser pulses properly designed. For this purpose, we adopt 2,5-dichloro [(3,6) pyrazinophane (DCPH) fixed on a surface, which is a real chiral aromatic molecule with plane chirality. Here π electrons can be rotated along the aromatic ring clockwise or counterclockwise by irradiation of a linearly polarized laser pulse with the properly designed photon polarization direction and the coherent ring current with the definite direction along the aromatic ring is prepared. This is contrast to ordinary ring current in an achiral aromatic ring molecule with degenerate electronic excited state, which is prepared by a circularly polarized laser [2]. In this case, π electrons rotate along the Z-axis of the laboratory coordinates, while for the present case electrons rotate along the z-axis in molecular Cartesian coordinates. It should be noted that signals originated from the coherent ring currents prepared by linearly polarized ultrashort UV lasers are specific to the chiral molecule of interest.

scholarly journals Spectroscopic analysis of high electric field enhanced ionization in laser filaments in air for corona guiding

2016 ◽  
Vol 4 ◽  
Author(s):  
Yingxia Wei ◽  
Yaoxiang Liu ◽  
Tie-Jun Wang ◽  
Na Chen ◽  
Jingjing Ju ◽  
...  
Keyword(s):  
Experimental Study ◽  
Femtosecond Laser ◽  
Electric Field ◽  
Corona Discharge ◽  
High Voltage ◽  
Fluorescence Spectra ◽  
Spectroscopic Analysis ◽  
Laser Pulses ◽  
Spectroscopic Measurement ◽  
High Electric Field

We report on a systematic experimental study on the fluorescence spectra produced from a femtosecond laser filament in air under a high electric field. The electric field alone was strong enough to create corona discharge (CD). Fluorescence spectra from neutral and ionic air molecules were measured and compared with pure high-voltage CD and pure laser filamentation (FIL). Among them, high electric field assisted laser FIL produced nitrogen fluorescence more efficiently than either pure CD or pure FIL processes. The nonlinear enhancement of fluorescence from the interaction of the laser filament and corona discharging electric field resulted in a more efficient ionization along the laser filament zone, which was confirmed by the spectroscopic measurement of both ionization-induced fluorescence and plasma-scattered 800 nm laser pulses. This is believed to be the key precursor process for filament-guided discharge.

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.

Post-solitons and electron vortices generated by femtosecond intense laser interacting with uniform near-critical-density plasmas

2021 ◽  
Author(s):  
Dong-Ning Yue ◽  
Min Chen ◽  
Yao Zhao ◽  
Pan-Fei Geng ◽  
Xiao-Hui Yuan ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Critical Density ◽  
Laser Pulses ◽  
Intense Laser ◽  
Nonlinear Structures ◽  
Particle In Cell ◽  
Laser Propagation ◽  
Laser Driver ◽  
Linearly Polarized ◽  
Dimensional Simulation

Abstract Generation of nonlinear structures, such as stimulated Raman side scattering waves, post-solitons and electron vortices, during ultra-short intense laser pulse transportation in near-critical-density (NCD) plasmas are studied by using multi-dimensional particle-in-cell (PIC) simulations. In two-dimensional geometries, both P- and S- polarized laser pulses are used to drive these nonlinear structures and to check the polarization effects on them. In the S-polarized case, the scattered waves can be captured by surrounding plasmas leading to the generation of post-solitons, while the main pulse excites convective electric currents leading to the formation of electron vortices through Kelvin-Helmholtz instability (KHI). In the P-polarized case, the scattered waves dissipate their energy by heating surrounding plasmas. Electron vortices are excited due to the hosing instability of the drive laser. These polarization dependent physical processes are reproduced in two different planes perpendicular to the laser propagation direction in three-dimensional simulation with linearly polarized laser driver. The current work provides inspiration for future experiments of laser-NCD plasma interactions.

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