Transverse spin dynamics in structured electromagnetic guided waves

Spin–momentum locking, a manifestation of topological properties that governs the behavior of surface states, was studied intensively in condensed-matter physics and optics, resulting in the discovery of topological insulators and related effects and their photonic counterparts. In addition to spin, optical waves may have complex structure of vector fields associated with orbital angular momentum or nonuniform intensity variations. Here, we derive a set of spin–momentum equations which describes the relationship between the spin and orbital properties of arbitrary complex electromagnetic guided modes. The predicted photonic spin dynamics is experimentally verified with four kinds of nondiffracting surface structured waves. In contrast to the one-dimensional uniform spin of a guided plane wave, a two-dimensional chiral spin swirl is observed for structured guided modes. The proposed framework opens up opportunities for designing the spin structure and topological properties of electromagnetic waves with practical importance in spin optics, topological photonics, metrology and quantum technologies and may be used to extend the spin-dynamics concepts to fluid, acoustic, and gravitational waves.

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Spin photonics: from transverse spin to photonic skyrmions

Nanophotonics ◽

10.1515/nanoph-2021-0046 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Peng Shi ◽

Luping Du ◽

Xiaocong Yuan

Keyword(s):

Electromagnetic Waves ◽

Guided Waves ◽

Spin Dynamics ◽

Near Field ◽

Longitudinal Optical ◽

Transverse Spin ◽

Strongly Coupled ◽

Spin Structures ◽

Structures And Properties ◽

The Mean

Abstract Spin angular momentum associated with circular polarization is a fundamental and important aspect of photons both in classical and quantum optics. The interaction of this optical spin with matter and structures results in many intriguing optical effects and state-of-the-art applications covered under the emerging subject of spin optics. Distinct from longitudinal optical spin along the mean wavevector, transverse spin, the corresponding vector of which is perpendicular to the mean wavevector, prevails and plays a significant role in confined electromagnetic waves such as focused beams, guided waves, and evanescent waves. In the optical near-field, these transverse spins are generated owing to the spatial variation of the kinetic momentum of confined electromagnetic waves, where the spin and orbital angular momenta are strongly coupled, leading to many interesting topological spin structures and properties. Several reviews on optical transverse spins have been published in recent years in which their concepts and the various configurations producing them were introduced systematically. Here, we introduce in this review the underlying physics and dynamics of transverse spin and the resultant topological structures and properties such as the photonic skyrmions and merons. We term this sub-area ‘spin photonics’, its scope being to cover the design and research of spin structures in strongly confined electromagnetic fields with unique properties and applications. The concepts and framework reviewed have importance in optics, topological photonics, metrology, and quantum technologies and may be used to extend spin-dynamics concepts to fluidic, acoustic, and gravitational waves.

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Ultrafast electron cycloids driven by the transverse spin of a surface acoustic wave

Science Advances ◽

10.1126/sciadv.abf7414 ◽

2021 ◽

Vol 7 (31) ◽

pp. eabf7414

Author(s):

Maximilian M. Sonner ◽

Farhad Khosravi ◽

Lisa Janker ◽

Daniel Rudolph ◽

Gregor Koblmüller ◽

...

Keyword(s):

Lithium Niobate ◽

Acoustic Wave ◽

Surface Acoustic Wave ◽

Acoustic Waves ◽

Spin Dynamics ◽

Surface Acoustic Waves ◽

Transverse Spin ◽

Cyclic Motion ◽

Industrial Relevance ◽

Spin Momentum

Spin-momentum locking is a universal wave phenomenon promising for applications in electronics and photonics. In acoustics, Lord Rayleigh showed that surface acoustic waves exhibit a characteristic elliptical particle motion strikingly similar to spin-momentum locking. Although these waves have become one of the few phononic technologies of industrial relevance, the observation of their transverse spin remained an open challenge. Here, we observe the full spin dynamics by detecting ultrafast electron cycloids driven by the gyrating electric field produced by a surface acoustic wave propagating on a slab of lithium niobate. A tubular quantum well wrapped around a nanowire serves as an ultrafast sensor tracking the full cyclic motion of electrons. Our acousto-optoelectrical approach opens previously unknown directions in the merged fields of nanoacoustics, nanophotonics, and nanoelectronics for future exploration.

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Boundary effects in transverse spin dynamics of spin-polarized quantum gases

Journal of Low Temperature Physics ◽

10.1007/bf00694082 ◽

1992 ◽

Vol 89 (3-4) ◽

pp. 539-542 ◽

Cited By ~ 2

Author(s):

S. Stepaniants ◽

A. E. Meyerovich

Keyword(s):

Spin Dynamics ◽

Quantum Gases ◽

Boundary Effects ◽

Transverse Spin ◽

Spin Polarized

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Realization of acoustic spin transport in metasurface waveguides

Nature Communications ◽

10.1038/s41467-020-18599-y ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 1

Author(s):

Yang Long ◽

Danmei Zhang ◽

Chenwen Yang ◽

Jianmin Ge ◽

Hong Chen ◽

...

Keyword(s):

Acoustic Waves ◽

Electromagnetic Waves ◽

Degrees Of Freedom ◽

Transport Processes ◽

Angular Momenta ◽

Transverse Electromagnetic ◽

Spin Texture ◽

Momentum Coupling ◽

Practical Implications ◽

Spin Momentum

Abstract Spin angular momentum enables fundamental insights for topological matters, and practical implications for information devices. Exploiting the spin of carriers and waves is critical to achieving more controllable degrees of freedom and robust transport processes. Yet, due to the curl-free nature of longitudinal waves distinct from transverse electromagnetic waves, spin angular momenta of acoustic waves in solids and fluids have never been unveiled only until recently. Here, we demonstrate a metasurface waveguide for sound carrying non-zero acoustic spin with tight spin-momentum coupling, which can assist the suppression of backscattering when scatters fail to flip the acoustic spin. This is achieved by imposing a soft boundary of the π reflection phase, realized by comb-like metasurfaces. With the special-boundary-defined spin texture, the acoustic spin transports are experimentally manifested, such as the suppression of acoustic corner-scattering, the spin-selected acoustic router with spin-Hall-like effect, and the phase modulator with rotated acoustic spin.

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Transverse Spin Dynamics in the Anisotropic Heisenberg Model Realized with Ultracold Atoms

Physical Review X ◽

10.1103/physrevx.11.041054 ◽

2021 ◽

Vol 11 (4) ◽

Author(s):

Paul Niklas Jepsen ◽

Wen Wei Ho ◽

Jesse Amato-Grill ◽

Ivana Dimitrova ◽

Eugene Demler ◽

...

Keyword(s):

Heisenberg Model ◽

Ultracold Atoms ◽

Spin Dynamics ◽

Transverse Spin ◽

Anisotropic Heisenberg Model

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Progress Review on Topological Properties of Heusler Materials

E3S Web of Conferences ◽

10.1051/e3sconf/202021302016 ◽

2020 ◽

Vol 213 ◽

pp. 02016

Author(s):

Zhi Lin

Keyword(s):

Hall Effect ◽

Surface States ◽

Anomalous Hall Effect ◽

Edge State ◽

Chiral Anomaly ◽

Dirac Fermion ◽

High Symmetry ◽

Heusler Compounds ◽

Topological Properties ◽

Topological State

Starting from crystal, electronic and magnetic structures of Heusler compounds, this paper studies the new topological materials related to Heusler compounds and their topological properties, such as anomalous Hall effect, skyrmions, chiral anomaly, Dirac fermion, Weyl fermion, transverse Nernst thermoelectric effect, thermal spintronics and topological surface states. It can be discovered that the topological state of Heusler compound can be well protected due to its high symmetry, thus producing rich topological properties. Heusler materials belonged to Weyl semimetals usually have strong anomalous Hall effect, and the Heusler materials with doping or Anomalous Nernst Effect (ANE) usually have higher thermoelectric figure of merit. These anomalous effects are closely related to the strong spin–orbit interaction. In application, people can use the non-dissipative edge state of quantum anomalous Hall effect to develop a new generation of low-energy transistors and electronic devices. The conversion efficiency of thermoelectric materials can be improved by ANE, and topological superconductivity can be used to promote the progress of quantum computation.

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NETWORKS OF SPRINGS: A PRACTICAL APPROACH

International Journal of Bifurcation and Chaos ◽

10.1142/s021812741002623x ◽

2010 ◽

Vol 20 (03) ◽

pp. 937-942 ◽

Cited By ~ 6

Author(s):

MASSIMILIANO ZANIN ◽

JAVIER M. BULDÚ ◽

STEFANO BOCCALETTI

Keyword(s):

Lower Energy ◽

Complex Structure ◽

Energy Output ◽

Linear Perturbation ◽

Random Structure ◽

Topological Properties ◽

Transmission Of Information ◽

Spatially Distributed ◽

Potential Applications ◽

Damping Systems

In the current work, we study the propagation of perturbations through networks of springs which are spatially distributed on a plane. We show that the topological properties of the network are related to the dissipation of energy within the system. By varying the rewiring parameter of the graph, and thus going from a regular to a random structure, we obtain a lower energy output, due to the fact that the initial (linear) perturbation is transformed into oscillations around each node. The results obtained are related to the transmission of information through a complex structure with potential applications to the design of more efficient damping systems.

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