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.

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 Brownian Swarm Dynamics and Burgers’ Equation with Higher Order Dispersion

Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 57
Author(s):  
Max-Olivier Hongler
Keyword(s):  
Burgers Equation ◽  
Higher Order ◽  
Underlying Structure ◽  
Swarm Dynamics ◽  
Special Cases ◽  
Kink Waves ◽  
Systematic Derivation ◽  
Fifth Order ◽  
Higher Order Dispersion ◽  
Order Dispersion

The concept of ranked order probability distribution unveils natural probabilistic interpretations for the kink waves (and hence the solitons) solving higher order dispersive Burgers’ type PDEs. Thanks to this underlying structure, it is possible to propose a systematic derivation of exact solutions for PDEs with a quadratic nonlinearity of the Burgers’ type but with arbitrary dispersive orders. As illustrations, we revisit the dissipative Kotrweg de Vries, Kuramoto-Sivashinski, and Kawahara equations (involving third, fourth, and fifth order dispersion dynamics), which in this context appear to be nothing but the simplest special cases of this infinitely rich class of nonlinear evolutions.

scholarly journals Influence of Even-Order Dispersion on Super-Sech Soliton Transmission Quality under Coherent Crosstalk

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
Aleksandra Panajotovic ◽  
Daniela Milovic ◽  
Anjan Biswas ◽  
Essaid Zerrad
Keyword(s):  
Fourth Order ◽  
Optical Network ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Higher Order ◽  
Trailing Edges ◽  
Even Order ◽  
Transmission Quality ◽  
The Impact ◽  
Order Dispersion

The transmission speed of optical network strongly depends on the impact of higher order dispersion. In presence of coherent crosstalk, which cannot be otherwise controlled by optical filtering, the impact of higher order dispersions becomes more pronounced. In this paper, the general expressions, that describe pulse deformation due to second- and fourth-order dispersions in a single-mode fiber, are given. The responses for such even-order dispersions, in presence of coherent crosstalk, are characterized by waveforms with long trailing edges. The transmission quality of optical pulses, due to both individual and combined influence of second- and fourth-order dispersions, is studied in this paper. Finally, the pulse shape and eye diagrams are obtained.

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