Wave-front restoration of orbital-angular-momentum beam based on phase diversity with GRNN

2021 ◽  
Author(s):  
Yuanzhi Su ◽  
Xiaoli Yin ◽  
Huan Chang ◽  
Zhaoyuan Zhang ◽  
Yuhang Liu
Keyword(s):  
Angular Momentum ◽  
Wave Front ◽  
Orbital Angular Momentum ◽  
Phase Diversity

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

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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