Angular momentum redirection phase of vector beams in a non-planar geometry

Abstract An electric field propagating along a non-planar path can acquire geometric phases. Previously, geometric phases have been linked to spin redirection and independently to spatial mode transformation, resulting in the rotation of polarisation and intensity profiles, respectively. We investigate the non-planar propagation of scalar and vector light fields and demonstrate that polarisation and intensity profiles rotate by the same angle. The geometric phase acquired is proportional to j = ℓ + σ, where ℓ is the topological charge and σ is the helicity. Radial and azimuthally polarised beams with j = 0 are eigenmodes of the system and are not affected by the geometric path. The effects considered here are relevant for systems relying on photonic spin Hall effects, polarisation and vector microscopy, as well as topological optics in communication systems.

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Spin-orbit interactions of transverse sound

Nature Communications ◽

10.1038/s41467-021-26375-9 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Shubo Wang ◽

Guanqing Zhang ◽

Xulong Wang ◽

Qing Tong ◽

Jensen Li ◽

...

Keyword(s):

Angular Momentum ◽

Geometric Phase ◽

Negative Refraction ◽

Spin Orbit ◽

Phase Effect ◽

Acoustic Activity ◽

Hall Effects ◽

Spin Orbit Interactions ◽

Spin Hall Effects ◽

Transverse Sound

AbstractSpin-orbit interactions (SOIs) endow light with intriguing properties and applications such as photonic spin-Hall effects and spin-dependent vortex generations. However, it is counterintuitive that SOIs can exist for sound, which is a longitudinal wave that carries no intrinsic spin. Here, we theoretically and experimentally demonstrate that airborne sound can possess artificial transversality in an acoustic micropolar metamaterial and thus carry both spin and orbital angular momentum. This enables the realization of acoustic SOIs with rich phenomena beyond those in conventional acoustic systems. We demonstrate that acoustic activity of the metamaterial can induce coupling between the spin and linear crystal momentum k, which leads to negative refraction of the transverse sound. In addition, we show that the scattering of the transverse sound by a dipole particle can generate spin-dependent acoustic vortices via the geometric phase effect. The acoustic SOIs can provide new perspectives and functionalities for sound manipulations beyond the conventional scalar degree of freedom and may open an avenue to the development of spin-orbit acoustics.

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An Inner- and Outer-Fed Dual-Arm Archimedean Spiral Antenna for Generating Multiple Orbital Angular Momentum Modes

Electronics ◽

10.3390/electronics8020251 ◽

2019 ◽

Vol 8 (2) ◽

pp. 251 ◽

Cited By ~ 9

Author(s):

Lulu Wang ◽

Huiyong Chen ◽

Kai Guo ◽

Fei Shen ◽

Zhongyi Guo

Keyword(s):

Angular Momentum ◽

Orbital Angular Momentum ◽

Topological Charge ◽

Communication Systems ◽

Spiral Antenna ◽

Dual Mode ◽

Archimedean Spiral ◽

Conical Cavity ◽

Measurement Results ◽

Dual Arm

Orbital angular momentum (OAM) beams have attracted great attention owing to their excellent performances in imaging and communication. In this paper, a dual-arm Archimedean spiral antenna (DASA) is proposed to generate multiple OAM states with positive and negative values by feeding at the inner and outer ends, respectively. The topological charge of radiated vortex waves is reconfigurable by tuning the operating frequency. Dual-mode OAM states are generated at different working frequencies (l = ±1 at 3 GHz, l = ±2 at 4 GHz, and l = ±3 at 4.8 GHz). Both the simulation and measurement results demonstrate that OAM beams can be generated effectively by the DASA. In addition, a conical cavity is used to increase the gain of the proposed DASA for more than 5 dBi in comparison to the traditional cylindrical cavity. Furthermore, the qualities of the generated OAM modes by the proposed DASA have been evaluated at different operating frequencies of 3 GHz, 4 GHz, and 4.8 GHz, respectively. The OAM modes purities of l = −1, −2, −3, 1, 2, and 3 are predominate with the proportion of about 81%, 70%, 74%, 78%, 77%, and 75%, respectively. Our results demonstrate that the proposed DASA has great potentials in OAM multiplexing communication systems.

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Inverse spin Hall effects in Nd doped SrTiO3

AIP Advances ◽

10.1063/1.4986324 ◽

2017 ◽

Vol 7 (12) ◽

pp. 125218

Author(s):

Qiuru Wang ◽

Wenxu Zhang ◽

Bin Peng ◽

Wanli Zhang

Keyword(s):

Hall Effects ◽

Spin Hall Effects

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High-Efficiency Spin-Related Vortex Metalenses

Nanomaterials ◽

10.3390/nano11061485 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1485

Author(s):

Wei Wang ◽

Ruikang Zhao ◽

Shilong Chang ◽

Jing Li ◽

Yan Shi ◽

...

Keyword(s):

Angular Momentum ◽

Orbital Angular Momentum ◽

Topological Charge ◽

High Efficiency ◽

Infrared Band ◽

Mid Infrared ◽

Integrated Devices ◽

Vortex Beams ◽

Topological Charges

In this paper, one spin-selected vortex metalens composed of silicon nanobricks is designed and numerically investigated at the mid-infrared band, which can produce vortex beams with different topological charges and achieve different spin lights simultaneously. Another type of spin-independent vortex metalens is also designed, which can focus the vortex beams with the same topological charge at the same position for different spin lights, respectively. Both of the two vortex metalenses can achieve high-efficiency focusing for different spin lights. In addition, the spin-to-orbital angular momentum conversion through the vortex metalens is also discussed in detail. Our work facilitates the establishment of high-efficiency spin-related integrated devices, which is significant for the development of vortex optics and spin optics.

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Anomalous spin Hall and inverse spin Hall effects in magnetic systems

Communications Physics ◽

10.1038/s42005-021-00557-9 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

X. R. Wang

Keyword(s):

Hall Effect ◽

Order Parameter ◽

Spin Current ◽

Spin Hall Effect ◽

Magnetic Systems ◽

Charge Current ◽

Spin Currents ◽

Tensor Quantity ◽

Hall Effects ◽

Spin Hall Effects

AbstractSpin current is a very important tensor quantity in spintronics. However, the well-known spin-Hall effect (SHE) can only generate a few of its components whose propagating and polarization directions are perpendicular with each other and to an applied charge current. It is highly desirable in applications to generate spin currents whose polarization can be in any possible direction. Here anomalous SHE and inverse spin-Hall effect (ISHE) in magnetic systems are predicted. Spin currents, whose polarisation and propagation are collinear or orthogonal with each other and along or perpendicular to the charge current, can be generated, depending on whether the applied charge current is along or perpendicular to the order parameter. In anomalous ISHEs, charge currents proportional to the order parameter can be along or perpendicular to the propagating or polarization directions of the spin current.

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Correction: Chen et al., Orbital Angular Momentum Generation and Detection by Geometric-Phase Based Metasurfaces. Appl. Sci. 2018, 8, 362

Applied Sciences ◽

10.3390/app8071134 ◽

2018 ◽

Vol 8 (7) ◽

pp. 1134 ◽

Cited By ~ 2

Author(s):

Menglin L. N. Chen ◽

Li Jun Jiang ◽

Wei E. I. Sha

Keyword(s):

Angular Momentum ◽

Orbital Angular Momentum ◽

Geometric Phase

We, the authors, wish to make the following corrections to our paper [...]

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Sectorial perturbation of vortex beams: Shannon entropy, orbital angular momentum and topological charge

Computer Optics ◽

10.18287/2412-6179-2019-43-5-723-734 ◽

2019 ◽

Vol 43 (5) ◽

pp. 723-734 ◽

Cited By ~ 6

Author(s):

A.V. Volyar ◽

M.V. Bretsko ◽

Ya.E. Akimova ◽

Yu.A. Egorov ◽

V.V. Milyukov

Keyword(s):

Angular Momentum ◽

Orbital Angular Momentum ◽

Shannon Entropy ◽

Topological Charge ◽

External Perturbation ◽

Informational Entropy ◽

Large Perturbation ◽

Wide Range ◽

Vortex Beams ◽

Computing Measuring

Transformations of the vortex beams structure subjected to sectorial perturbation were theoretically and experimentally studied. The analysis was based on computing (measuring) the vortex spectrum that enables us to find the orbital angular momentum (OAM) and Shannon entropy (informational entropy). We have revealed that, in the general case, the number of vortices caused by an external perturbation is not related to the topological charge. For arbitrary perturbation, the topological charge remains equal to the initial topological charge of the unperturbed vortex beam. Growth of the vortex number induced by perturbations is associated with the optical uncertainty principle between the sectorial angle and the OAM. The computer simulation has shown that OAM does not depend on the number of vortices induced by perturbations. Moreover, two maxima are formed both in the positive and negative regions of the vortex spectrum. As a result, the OAM does not practically change in a wide range of perturbation angles from 0 to 90 °. However, at large perturbation angles, when the energy is almost equally redistributed between the vortex modes with opposite signs of the topological charge, the OAM rapidly decreases. At the same time, the Shannon entropy monotonically increases with growing perturbation angle. This is due to the fact that the entropy depends only on the number of vortex states caused by external perturbations.

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High-Dimensional Pixel Entanglement: Efficient Generation and Certification

Quantum ◽

10.22331/q-2020-12-24-376 ◽

2020 ◽

Vol 4 ◽

pp. 376

Author(s):

Natalia Herrera Valencia ◽

Vatshal Srivastav ◽

Matej Pivoluska ◽

Marcus Huber ◽

Nicolai Friis ◽

...

Keyword(s):

Carrying Capacity ◽

Communication Systems ◽

Degrees Of Freedom ◽

State Of The Art ◽

Quality Measurement ◽

High Dimensional ◽

Single Photons ◽

Spatial Mode ◽

Classical Communication ◽

Entanglement Of Formation

Photons offer the potential to carry large amounts of information in their spectral, spatial, and polarisation degrees of freedom. While state-of-the-art classical communication systems routinely aim to maximize this information-carrying capacity via wavelength and spatial-mode division multiplexing, quantum systems based on multi-mode entanglement usually suffer from low state quality, long measurement times, and limited encoding capacity. At the same time, entanglement certification methods often rely on assumptions that compromise security. Here we show the certification of photonic high-dimensional entanglement in the transverse position-momentum degree-of-freedom with a record quality, measurement speed, and entanglement dimensionality, without making any assumptions about the state or channels. Using a tailored macro-pixel basis, precise spatial-mode measurements, and a modified entanglement witness, we demonstrate state fidelities of up to 94.4% in a 19-dimensional state-space, entanglement in up to 55 local dimensions, and an entanglement-of-formation of up to 4 ebits. Furthermore, our measurement times show an improvement of more than two orders of magnitude over previous state-of-the-art demonstrations. Our results pave the way for noise-robust quantum networks that saturate the information-carrying capacity of single photons.

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