scholarly journals Compact cascaded meta-surface system for controlling the spin and orbital angular momentum of electromagnetic fields simultaneously

2021 ◽  
Author(s):  
Pei Yang ◽  
Rui Yang ◽  
Yachao Li
Keyword(s):  
Angular Momentum ◽  
Electromagnetic Fields ◽  
Orbital Angular Momentum ◽  
Surface System

scholarly journals On the dragging of light by a rotating medium

2007 ◽  
Vol 463 (2085) ◽  
pp. 2185-2194 ◽  
Author(s):  
Jörg B Götte ◽  
Stephen M Barnett ◽  
Miles Padgett
Keyword(s):  
Wave Equation ◽  
Angular Momentum ◽  
Electromagnetic Fields ◽  
Orbital Angular Momentum ◽  
Optical Polarization ◽  
Rotating Medium

When light is passing through a rotating medium the optical polarization is rotated. Recently, it has been reasoned that this rotation applies also to the transmitted image. We examine these two phenomena by extending an analysis of Player (Player 1976 Proc. R. Soc. A 349 , 441–445) to general electromagnetic fields. We find that in this more general case, the wave equation inside the rotating medium has to be amended by a term which is connected to the orbital angular momentum (OAM) of the light. We show that optical spin and OAM account for the rotation of the polarization and the rotation of the transmitted image, respectively.

scholarly journals The angular momentum of vectorial non-paraxial fields and the role of radial charges in orbit-spin coupling

2020 ◽  
Vol 238 ◽  
pp. 12017
Author(s):  
Omar El Gawhary ◽  
Paul Urbach
Keyword(s):  
Angular Momentum ◽  
Electromagnetic Fields ◽  
Orbital Angular Momentum ◽  
Total Angular Momentum ◽  
Polarization State ◽  
Spin Coupling ◽  
Spin Orbit Coupling ◽  
Spin Angular Momentum ◽  
Phase Profile

Electromagnetic fields carry a linear and an angular momentum, the first being responsible for the existence of the radiation pressure and the second for the transfer of torque from electromagnetic radiation to matter. The angular momentum is considered to have two components, one due to the polarization state of the field, usually called Spin Angular Momentum (SAM), and one due to existence of topological azimuthal charges in the field phase profile, which leads to the Orbital Angular Momentum (OAM). For non-paraxial fields these two contributions are not independent of each other, something which is described as spin-orbit coupling. It has been recently proved that electromagnetic fields necessarily carry also invariant radial charges that, as discussed in this work, play a key role in the angular momentum. Here we show that the total angular momentum consists in fact of three components: one component only dependent on the spin of the field, another dependent on the azimuthal charges carried by the field and a third component dependent on the spin and the radial charges contained in the field. By properly controlling the number and coupling among these radial charges it is possible to design electromagnetic fields with a desired total angular momentum. In this way it is also possible to discover fields with no orbital angular momentum and a spin angular momentum typical of spin-3/2 objects, irrespective of the fact that photons are spin-1 particles.

Detection of Rotational Object in Squint Sight Based on Orbital Angular Momentum

2019 ◽  
Author(s):  
Yu Wang ◽  
Kang Liu ◽  
Hongyan Liu ◽  
Yuliang Qin ◽  
Xingyue Liu
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum

Advanced Mode Unity Using Loop Antennas Proximate to Reflector for Orbital Angular Momentum Communication

2018 ◽  
Author(s):  
Ryohei Yamagishi ◽  
Hiroto Otsuka ◽  
Ryo Ishikawa ◽  
Akira Saitou ◽  
Hiroshi Suzuki ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Loop Antennas

scholarly journals Numerical study of momentum and energy transfer in the interaction of a laser pulse carrying orbital angular momentum with electrons

2020 ◽  
Vol 37 ◽  
pp. 100863
Author(s):  
V.T. Tikhonchuk ◽  
Ph. Korneev ◽  
E. Dmitriev ◽  
R. Nuter
Keyword(s):  
Energy Transfer ◽  
Angular Momentum ◽  
Laser Pulse ◽  
Orbital Angular Momentum ◽  
Numerical Study

Highly dispersive coupled ring-core fiber for orbital angular momentum modes

2020 ◽  
Vol 117 (19) ◽  
pp. 191101
Author(s):  
Wenpu Geng ◽  
Yiqiao Li ◽  
Yuxi Fang ◽  
Yingning Wang ◽  
Changjing Bao ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Core Fiber ◽  
Ring Core

scholarly journals Modal coupling and crosstalk due to turbulence and divergence on free space THz links using multiple orbital angular momentum beams

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhe Zhao ◽  
Runzhou Zhang ◽  
Hao Song ◽  
Kai Pang ◽  
Ahmed Almaiman ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Atmospheric Turbulence ◽  
Channel Capacity ◽  
Orbital Angular Momentum ◽  
Beam Waist ◽  
Modal Coupling ◽  
Divergence Effect ◽  
Power Leakage ◽  
Calm Weather ◽  
Bad Weather

AbstractOrbital-angular-momentum (OAM) multiplexing has been utilized to increase the channel capacity in both millimeter-wave and optical domains. Terahertz (THz) wireless communication is attracting increasing attention due to its broadband spectral resources. Thus, it might be valuable to explore the system performance of THz OAM links to further increase the channel capacity. In this paper, we study through simulations the fundamental system-degrading effects when using multiple OAM beams in THz communications links under atmospheric turbulence. We simulate and analyze the effects of divergence, turbulence, limited-size aperture, and misalignment on the signal power and crosstalk of THz OAM links. We find through simulations that the system-degrading effects are different in two scenarios with atmosphere turbulence: (a) when we consider the same strength of phasefront distortion, faster divergence (i.e., lower frequency; smaller beam waist) leads to higher power leakage from the transmitted mode to neighbouring modes; and (b) however, when we consider the same atmospheric turbulence, the divergence effect tends to affect the power leakage much less, and the power leakage increases as the frequency, beam waist, or OAM order increases. Simulation results show that: (i) the crosstalk to the neighbouring mode remains < − 15 dB for a 1-km link under calm weather, when we transmit OAM + 4 at 0.5 THz with a beam waist of 1 m; (ii) for the 3-OAM-multiplexed THz links, the signal-to-interference ratio (SIR) increases by ~ 5–7 dB if the mode spacing increases by 1, and SIR decreases with the multiplexed mode number; and (iii) limited aperture size and misalignment lead to power leakage to other modes under calm weather, while it tends to be unobtrusive under bad weather.

scholarly journals Switchable X-Ray Orbital Angular Momentum from an Artificial Spin Ice

2021 ◽  
Vol 126 (11) ◽  
Author(s):  
Justin S. Woods ◽  
Xiaoqian M. Chen ◽  
Rajesh V. Chopdekar ◽  
Barry Farmer ◽  
Claudio Mazzoli ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Spin Ice ◽  
X Ray ◽  
Artificial Spin Ice
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