scholarly journals Wavelength-Dependent Features of Photoelectron Spectra from Nanotip Photoemission

Photonics ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 129
Author(s):  
Xiao-Yuan Wu ◽  
Hao Liang ◽  
Marcelo F. Ciappina ◽  
Liang-You Peng
Keyword(s):  
Strong Field ◽  
Field Enhancement ◽  
Laser Pulses ◽  
High Energy ◽  
Classical Trajectory ◽  
Photoelectron Spectra ◽  
Radius Of Curvature ◽  
High Electron ◽  
Electron Dynamics ◽  
Classical Trajectory Monte Carlo

If a metal nanotip is irradiated with the light of a wavelength much larger than the nanotip’s radius of curvature, optical near-fields become excited. These fields are responsible for distinct strong-field electron dynamics, due to both the field enhancement and spatial localization. By classical trajectory, Monte Carlo (CTMC) simulation, and the integration of the time-dependent Schrödinger equation (TDSE), we find that the photoelectron spectra for nanotip strong-field photoemission, irradiated by mid-infrared laser pulses, present distinctive wavelength-dependent features, especially in the mid- to high-electron energy regions, which are different from the well known ones. By extracting the electron trajectories from the CTMC simulation, we investigate these particular wavelength-dependent features. Our theoretical results contribute to understanding the photoemission and electron dynamics at nanostructures, and pave new pathways for designing high-energy nanometer-sized ultrafast electron sources.

scholarly journals Theoretical framework for classification and prediction of ultrafast and strong-field phenomena in solids

2019 ◽  
Vol 205 ◽  
pp. 04013
Author(s):  
Stanislav Yu. Kruchinin ◽  
Ferenc Krausz ◽  
Vladislav S. Yakovlev
Keyword(s):  
Density Matrix ◽  
Time Scales ◽  
Strong Field ◽  
Laser Pulses ◽  
Theoretical Framework ◽  
Ultrashort Laser Pulses ◽  
Matrix Equations ◽  
Electron Dynamics ◽  
Characteristic Energy ◽  
Ultrashort Laser

We study the characteristic energy and time scales describing the coherent electron dynamics and decoherence phenomena in solids interacting with ultrashort laser pulses. Our analysis resulted in the derivation system of dimensionless adiabaticity parameters and derivation of the non-Markovian density-matrix equations applicable on arbitrary short timescales.

scholarly journals Lightwave-controlled electron dynamics in graphene

2019 ◽  
Vol 205 ◽  
pp. 05002
Author(s):  
Christian Heide ◽  
Takuya Higuchi ◽  
Konrad Ullmann ◽  
Heiko B. Weber ◽  
Peter Hommelhoff
Keyword(s):  
Strong Field ◽  
Polarized Light ◽  
Laser Pulses ◽  
Weak Field ◽  
Ultrashort Laser Pulses ◽  
Electron Dynamics ◽  
Matter Interaction ◽  
Linearly Polarized ◽  
Light Matter Interaction ◽  
Optical Cycle

We demonstrate that currents induced in graphene by ultrashort laser pulses are sensitive to the exact shape of the electric-field waveform. By increasing the field strength, we found a transition of the light–matter interaction from the weak-field to the strong-field regime at around 2 V/nm, where intraband dynamics influence interband transitions. In this strong-field regime, the light-matter interaction can be described by the wavenumber trajectories of electrons in the reciprocal space. For linearly polarized light the electron dynamics are governed by repeated sub-optical-cycle Landau-Zener transitions between the valence- and conduction band, resulting in Landau-Zener-Stuckelberg interference, whereas for circular polarized light this interference is supressed.

FREQUENCY EFFECTS AND CLASSICAL PATHS IN STRONG-FIELD IONIZATION

1995 ◽  
Vol 04 (03) ◽  
pp. 687-700
Author(s):  
H. R. REISS
Keyword(s):  
High Frequency ◽  
Field Experiments ◽  
Strong Field ◽  
Polarized Light ◽  
High Energy ◽  
Frequency Theory ◽  
Photoelectron Spectra ◽  
Energy Conditions ◽  
Circularly Polarized Light ◽  
Wide Range

The ability of the SFA (strong-field approximation) to predict the ionization of atoms at all frequencies is explored at low frequency by comparison with experiment. Excellent agreement is found over a very wide range of high intensities. At high frequency, where no precision strong-field experiments are available, a comparison is made between predictions of the SFA and a high-frequency theory due to Gavrila. Agreement in transition rates is very good. The disagreement in the assignment of energy conditions at high frequencies is explained as a difference in interpretation brought about by the gauge transformation employed by Gavrila. An examination of semiclassical path behavior of a photoelectron after ionization gives insight on the lower limits of intensity for which the SFA is applicable, and makes transparent the meaning of a recently applied Coulomb correction to the SFA for circularly polarized light. A related examination for linearly polarized light gives an effective high energy limit for intense-field photoelectron spectra.

scholarly journals Study of the Effect of Higher-order Dispersions on Photoionisation Induced by Ultrafast Laser Pulses Applying a Classical Theoretical Method

2021 ◽  
Author(s):  
István Márton ◽  
László Sarkadi
Keyword(s):  
Theoretical Method ◽  
Laser Pulses ◽  
Classical Trajectory ◽  
Higher Order ◽  
Group Delay Dispersion ◽  
Central Wavelength ◽  
Ultrafast Laser Pulses ◽  
Left Right Asymmetry ◽  
Classical Trajectory Monte Carlo ◽  
Order Dispersion

Abstract We investigated the effect of higher order dispersion on ultrafast photoionisation with Classical Trajectory Monte Carlo (CTMC) method for hydrogen and krypton atoms. In our calculations we used linearly polarised ultrashort 7 fs laser pulses, 6.5 × 1014 W/cm2 intensity, and a central wavelength of 800 nm. Our results show that electrons with the highest kinetic energies are obtained with transform limited (TL) pulses. The shaping of the pulses with negative second- third- or fourth- order dispersion results in higher ionisation yield and electron energies compared to pulses shaped with positive dispersion values. We have also investigated how the Carrier Envelope Phase (CEP) dependence of the ionisation is infuenced by dispersion. We calculated the left-right asymmetry as a function of energy and CEP for sodium atoms employing pulses of 4.5 fs, 800 nm central wavelength, and 4 × 1012 W/cm2 intensity. We found that the left-right asymmetry is more pronounced for pulses shaped with positive Group Delay Dispersion (GDD). It was also found that shaping a pulse with increasing amounts of GDD in absolute value blurs the CEP dependence, which is attributed to the increasing number of optical cycles.

Strong Field Atomic Ionization: Origin of High-Energy Structures in Photoelectron Spectra

2003 ◽  
Vol 90 (1) ◽  
Author(s):  
Joseph Wassaf ◽  
Valérie Véniard ◽  
Richard Taïeb ◽  
Alfred Maquet
Keyword(s):  
Strong Field ◽  
High Energy ◽  
Photoelectron Spectra ◽  
Atomic Ionization

scholarly journals Selective strong-field enhancement and suppression of ionization with short laser pulses

2016 ◽  
Vol 93 (6) ◽  
Author(s):  
N. A. Hart ◽  
J. Strohaber ◽  
A. A. Kolomenskii ◽  
G. G. Paulus ◽  
D. Bauer ◽  
...  
Keyword(s):  
Strong Field ◽  
Field Enhancement ◽  
Laser Pulses ◽  
Short Laser Pulses

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.

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