scholarly journals Ultrafast attosecond-magnetic-field generationof the charge migration process based onelectronically excited HeH²+ and H₂++ bycircularly polarized laser pulses

2021 ◽  
Author(s):  
qing yun Xu ◽  
Zhijie Yang ◽  
Yong He ◽  
Fang Gao ◽  
Huizhong Lu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Laser Pulses ◽  
Migration Process ◽  
Charge Migration

scholarly journals Electron Symmetry Breaking during Attosecond Charge Migration Induced by Laser Pulses: Point Group Analyses for Quantum Dynamics

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 205
Author(s):  
Dietrich Haase ◽  
Gunter Hermann ◽  
Jörn Manz ◽  
Vincent Pohl ◽  
Jean Christophe Tremblay
Keyword(s):  
Laser Pulse ◽  
Symmetry Breaking ◽  
Electric Fields ◽  
Quantum Dynamics ◽  
Point Group ◽  
Laser Pulses ◽  
Charge Migration ◽  
Laser Control ◽  
The One ◽  
Superposition States

Quantum simulations of the electron dynamics of oriented benzene and Mg-porphyrin driven by short (<10 fs) laser pulses yield electron symmetry breaking during attosecond charge migration. Nuclear motions are negligible on this time domain, i.e., the point group symmetries G = D6h and D4h of the nuclear scaffolds are conserved. At the same time, the symmetries of the one-electron densities are broken, however, to specific subgroups of G for the excited superposition states. These subgroups depend on the polarization and on the electric fields of the laser pulses. They can be determined either by inspection of the symmetry elements of the one-electron density which represents charge migration after the laser pulse, or by a new and more efficient group-theoretical approach. The results agree perfectly with each other. They suggest laser control of symmetry breaking. The choice of the target subgroup is restricted, however, by a new theorem, i.e., it must contain the symmetry group of the time-dependent electronic Hamiltonian of the oriented molecule interacting with the laser pulse(s). This theorem can also be applied to confirm or to falsify complementary suggestions of electron symmetry breaking by laser pulses.

scholarly journals Coherent Exciton Dynamics in Ensembles of Size-Dispersed CdSe Quantum Dot Dimers Probed via Ultrafast Spectroscopy: A Quantum Computational Study

2020 ◽  
Vol 10 (4) ◽  
pp. 1328 ◽  
Author(s):  
Hugo Gattuso ◽  
Barbara Fresch ◽  
Raphael D. Levine ◽  
Françoise Remacle
Keyword(s):  
Transient Absorption ◽  
Computational Study ◽  
Laser Pulses ◽  
Transient Absorption Spectroscopy ◽  
Basis Set ◽  
Charge Migration ◽  
Pump Probe ◽  
Electronic Response ◽  
Charge Transfer Excitons ◽  
Interdot Coupling

Interdot coherent excitonic dynamics in nanometric colloidal CdSe quantum dots (QD) dimers lead to interdot charge migration and energy transfer. We show by electronic quantum dynamical simulations that the interdot coherent response to ultrashort fs laser pulses can be characterized by pump-probe transient absorption spectroscopy in spite of the inevitable inherent size dispersion of colloidal QDs. The latter, leading to a broadening of the excitonic bands, induce accidental resonances that actually increase the efficiency of the interdot coupling. The optical electronic response is computed by solving the time-dependent Schrodinger equation including the interaction with the oscillating electric field of the pulses for an ensemble of dimers that differ by their size. The excitonic Hamiltonian of each dimer is parameterized by the QD size and interdot distance, using an effective mass approximation. Local and charge transfer excitons are included in the dimer basis set. By tailoring the QD size, the excitonic bands can be tuned to overlap and thus favor interdot coupling. Computed pump-probe transient absorption maps averaged over the ensemble show that the coherence of excitons in QD dimers that lead to interdot charge migration can survive size disorder and could be observed in fs pump-probe, four-wave mixing, or covariance spectroscopy.

scholarly journals Leptons from decay of mesons in the laser-induced particle pulse from ultra-dense protium p(0)

2016 ◽  
Vol 25 (10) ◽  
pp. 1650085 ◽  
Author(s):  
Leif Holmlid
Keyword(s):  
Magnetic Field ◽  
Beta Decay ◽  
Direct Observation ◽  
Weak Magnetic Field ◽  
Laser Pulses ◽  
Metal Foils ◽  
Decay Times ◽  
Magnetic Deflection

Kaons and pions are observed by their characteristic decay times of 12, 52 and 26 ns after impact of relatively weak ns-long laser pulses on ultra-dense hydrogen H(0), as reported previously. The signal using an ultra-dense protium p(0) generator with natural hydrogen is now studied. Deflection in a weak magnetic field or penetration through metal foils cannot distinguish between the types of decaying mesons. The signals observed are thus not caused by the decaying mesons themselves, but by the fast particles often at [Formula: see text][Formula: see text]MeV u[Formula: see text] formed in their decay. The fast particles are concluded to be mainly muons from their relatively small magnetic deflection and strong penetration. This is further supported by published studies on the direct observation of the beta decay of muons in scintillators and solid converters using the same type of p(0) generator.

scholarly journals Mechanism of merging of torsional Alfven and slow magnetosonic waves produced by train of laser pulses upon irradiation of a target located in a space plasma with a magnetic field. Laboratory modeling

2017 ◽  
Author(s):  
V. N. Tischenko ◽  
Yu. P. Zakharov ◽  
V. G. Posukh ◽  
A. G. Berezutsky ◽  
E. L. Boyarintsev ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Space Plasma ◽  
Laser Pulses ◽  
Laboratory Modeling ◽  
Field Laboratory

scholarly journals External Field-Controlled Ablation: Magnetic Field

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1662 ◽  
Author(s):  
Jovan Maksimovic ◽  
Soon Hock Ng ◽  
Tomas Katkus ◽  
Bruce C. C. Cowie ◽  
Saulius Juodkazis
Keyword(s):  
Magnetic Field ◽  
External Field ◽  
Surface Plasmon Polariton ◽  
Femtosecond Laser Ablation ◽  
Laser Pulses ◽  
Periodic Patterns ◽  
Fs Laser ◽  
Application Potential ◽  
Field Lines ◽  
The Magnetic Field

The femtosecond laser ablation of silicon amidst an externally applied magnetic field in different orientations was investigated with respect to the scanning direction and polarisation of the laser beam, by observation of ablation patterns and debris displacement in a range of fluences, magnetic fields strengths, and geometries. Ultra-short ∼ 230 fs laser pulses of 1030 nm wavelengths were utilised in the single and multi-pulse irradiation modes. Ablation with an externally applied magnetic B-field B e x t ≈ 0.15 T was shown to strongly affect debris formation and deposition. The mechanism of surface plasmon polariton (SPP) wave can explain the ablated periodic patterns observed with alignment along the magnetic field lines. The application potential of external field controlled ablation is discussed.

scholarly journals Electromagnetic Burst Generation during Annihilation of Magnetic Field in Relativistic Laser-Plasma Interaction

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Y. J. Gu ◽  
F. Pegoraro ◽  
P. V. Sasorov ◽  
D. Golovin ◽  
A. Yogo ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Current Sheet ◽  
Laser Plasma ◽  
Laser Pulses ◽  
Opposite Polarity ◽  
Laboratory Modeling ◽  
Relativistic Limit ◽  
Plasma Target ◽  
Formation And Evolution ◽  
Underdense Plasma

AbstractWe present the results of theoretical studies of formation and evolution of the current sheet in a colliosionless plasma during magnetic reconnection in relativistic limit. Relativistic magnetic reconnection is driven by parallel laser pulses interacting with underdense plasma target. Annihilation of laser created magnetic field of opposite polarity generates strong non-stationary electric field formed in between the region with opposite polarity magnetic field accelerating charged particles within the current sheet. This laser-plasma target configuration is discussed in regard with the laboratory modeling of charged particle acceleration and gamma flash generation in astrophysics. We present the results of 3-dimensional kinetic simulations and theoretical studies on the formation and evolution of the current sheet in a collisionless plasma during magnetic field annihilation in the ultra-relativistic limit. Annihilation of oppositively directed magnetic fields driven by two laser pulses interacting with underdense plasma target is accompanied by an electromagnetic burst generation. The induced strong non-stationary longitudinal electric field accelerates charged particles within the current sheet. Properties of the laser-plasma target configuration are discussed in the context of the laboratory modeling for charged particle acceleration and gamma flash generation in astrophysics.

Terahertz radiation from a shallow incidence-angle InAs emitter in a magnetic field irradiated with femtosecond laser pulses

2001 ◽  
Vol 40 (9) ◽  
pp. 1369 ◽  
Author(s):  
Shingo Ono ◽  
Takeyo Tsukamoto ◽  
Eiji Kawahata ◽  
Takayuki Yano ◽  
Hideyuki Ohtake ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Femtosecond Laser ◽  
Terahertz Radiation ◽  
Incidence Angle ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses
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