Coherent π-electron dynamics of (P)-2,2′-biphenol induced by ultrashort linearly polarized UV pulses: Angular momentum and ring current

2013 ◽  
Vol 138 (7) ◽  
pp. 074304 ◽  
Author(s):  
H. Mineo ◽  
S. H. Lin ◽  
Y. Fujimura
Keyword(s):  
Angular Momentum ◽  
Ring Current ◽  
Electron Dynamics ◽  
Linearly Polarized

scholarly journals Quantum Control of Coherent π-Electron Dynamics in Aromatic Ring Molecules

2021 ◽  
Vol 9 ◽  
Author(s):  
Hirobumi Mineo ◽  
Ngoc-Loan Phan ◽  
Yuichi Fujimura
Keyword(s):  
Magnetic Field ◽  
Angular Momentum ◽  
Aromatic Ring ◽  
Excited States ◽  
Quantum Control ◽  
Ring Current ◽  
Theoretical Description ◽  
Electron Dynamics ◽  
Ring Molecules ◽  
Electron Ring

Herein we review a theoretical study of unidirectional π-electron rotation in aromatic ring molecules, which originates from two quasi-degenerate electronic excited states created coherently by a linearly polarized ultraviolet/visible laser with a properly designed photon polarization direction. Analytical expressions for coherent π-electron angular momentum, ring current and ring current-induced magnetic field are derived in the quantum chemical molecular orbital (MO) theory. The time evolution of the angular momentum and the ring current are expressed using the density matrix method under Markov approximation or by solving the time-dependent Schrödinger equation. In this review we present the results of the following quantum control scenarios after a fundamental theoretical description of coherent angular momentum, ring current and magnetic field: first, two-dimensional coherent π-electron dynamics in a non-planar (P)-2,2’-biphenol molecule; second, localization of the coherent π-electron ring current to a designated benzene ring in polycyclic aromatic hydrocarbons; third, unidirectional π-electron rotations in low-symmetry aromatic ring molecules based on the dynamic Stark shift of two relevant excited states that form a degenerate state using the non-resonant ultraviolet lasers. The magnetic fields induced by the coherent π-electron ring currents are also estimated, and the position dependence of the magnetic fluxes is demonstrated.

scholarly journals Laser-Control of Ultrafast π-Electron Ring Currents in Aromatic Molecules: Roles of Molecular Symmetry and Light Polarization

2018 ◽  
Vol 8 (12) ◽  
pp. 2347 ◽  
Author(s):  
Manabu Kanno ◽  
Hirohiko Kono ◽  
Yuichi Fujimura
Keyword(s):  
Angular Momentum ◽  
Optical Switching ◽  
Ring Current ◽  
Molecular Vibration ◽  
Vibrational Amplitude ◽  
Electron Dynamics ◽  
Aromatic Molecules ◽  
Ring Currents ◽  
Laser Control ◽  
Ultrafast Electron Dynamics

Being motivated by the recent progress in attosecond laser technology, we theoretically explore the strategy of inducing ultrafast electron dynamics inherent to aromatic molecules, i.e., ring currents by means of polarized laser pulses. The main topic of discussion is how to control the direction of ring currents in an aromatic molecule of low symmetry, for which the design of an efficient control pulse cannot be achieved intuitively. We first consider a system with a single aromatic ring and show that coherent π-electron angular momentum, which oscillates with time, can be produced and controlled by a polarized laser pulse with its ellipticity and orientation properly chosen. Nonadiabatic couplings with molecular vibration gradually weaken the angular momentum, while the vibrational amplitude strongly depends on the polarization of incident light. This suggests the conversion of the polarization dependence of ring current into that of subsequent vibration, which may open a way to detect laser-driven ultrafast electron dynamics by vibrational spectroscopy. The laser-control scheme for the ring current is then extended to a molecule with two aromatic rings, which exhibits characteristic phenomena absent in that with a single ring. We demonstrate that two-dimensional switching of the direction of angular momentum is possible in such molecules. In addition, ring current can be localized at a specific ring by tailored lasers. The application of the present control method to polycyclic aromatic hydrocarbons will lead to the development of next-generation organic optical switching devices.

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 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.

scholarly journals Trapping and rotation of microparticles using a metasurface exciting by linearly polarized beam

2021 ◽  
Vol 11 ◽  
pp. 184798042110151
Author(s):  
Yi Yang ◽  
Siyuan Huang
Keyword(s):  
Angular Momentum ◽  
Surface Plasmon ◽  
Orbital Angular Momentum ◽  
Surface Plasmon Polariton ◽  
Polarized Beams ◽  
Archimedes Spiral ◽  
Clockwise Direction ◽  
Polarized Beam ◽  
Linearly Polarized ◽  
Plasmon Polariton

We numerically demonstrate trapping and rotation of particles using a metasurface formed by arranging nanocavities as a right-handed Archimedes’ spiral. Excited by a 90° linearly polarized beam, a focused surface plasmon polariton (SPP) field is formed at the center of the spiral, and the particle can be trapped by the field. While excited by −45° linearly polarized beams, a vortex SPP field carrying orbital angular momentum is formed, and the particles can be trapped and rotated in the clockwise direction at the vortex field.

scholarly journals Vortex energy flow in the tight focus of a non-vortex field with circular polarization

2020 ◽  
Vol 44 (1) ◽  
pp. 5-11
Author(s):  
V.V. Kotlyar ◽  
S.S. Stafeev ◽  
A.G. Nalimov
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Energy Flow ◽  
Poynting Vector ◽  
Focal Spot ◽  
Free Field ◽  
Longitudinal Component ◽  
Circularly Polarized ◽  
Linearly Polarized ◽  
Direct Energy

Using Richards-Wolf formulas, we show that an axisymmetric circularly polarized vortex-free field can be focused into a sharp subwavelength focal spot, around which there is a region where the light energy flow propagates along a spiral. This effect can be explained by the conversion of the spin angular momentum of the circularly polarized field into the orbital angular momentum near the focus, although the on-axis orbital angular momentum remains zero. It is also shown that a linearly polarized optical vortex with topological charge 2 forms near the focal plane an on-axis reverse energy flow (defined by the negative longitudinal component of the Poynting vector) whose amplitude is comparable with the direct energy flow.

scholarly journals A Review of Tunable Orbital Angular Momentum Modes in Fiber: Principle and Generation

2019 ◽  
Vol 9 (12) ◽  
pp. 2408 ◽  
Author(s):  
Lipeng Feng ◽  
Yan Li ◽  
Sihan Wu ◽  
Wei Li ◽  
Jifang Qiu ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Rotation Speed ◽  
Degree Of Freedom ◽  
Particle Rotation ◽  
Large Capacity ◽  
Linearly Polarized ◽  
Basic Concepts ◽  
Polarization States ◽  
Linearly Polarized Modes

Orbital angular momentum (OAM) beams, a new fundamental degree of freedom, have excited a great diversity of interest due to a variety of emerging applications. The scalability of OAM has always been a topic of discussion because it plays an important role in many applications, such as expanding to large capacity and adjusting the trapped particle rotation speed. Thus, the generation of arbitrary tunable OAM mode has been paid increasing attention. In this paper, the basic concepts of classical OAM modes are introduced firstly. Then, the tunable OAM modes are categorized into three types according to the orbital angular momentums and polarization states of mode carrying. In order to understand the OAM evolution of a mode intuitively, three kinds of Poincaré spheres (PSs) are introduced to represent the three kinds of tunable OAM modes. Numerous methods generating tunable OAM modes can be roughly divided into two types: spatial and fiber-based generation methods. The principles of fiber-based generation methods are interpreted by introducing two mode bases (linearly-polarized modes and vector modes) of the fiber. Finally, the strengths and weaknesses of each generation method are pointed out and the key challenges for tunable OAM modes are discussed.

scholarly journals Modeling ring current ion and electron dynamics and plasma instabilities during a high-speed stream driven storm

2012 ◽  
Vol 117 (A9) ◽  
pp. n/a-n/a ◽  
Author(s):  
V. K. Jordanova ◽  
D. T. Welling ◽  
S. G. Zaharia ◽  
L. Chen ◽  
R. M. Thorne
Keyword(s):  
High Speed ◽  
Ring Current ◽  
Plasma Instabilities ◽  
Electron Dynamics ◽  
High Speed Stream
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