Results 21 to 30 of about 657 (221)

Design, Testing and Performance Evaluation of Beam Positioning System for Free Space Optical Communication System [PDF]

open access: yesRadioengineering, 2021
Beam wandering and the wavefront distortion are the significant sources for the power loss in Wireless Optical Communication (WOC). In this paper Full Factorial Design (FFD) and Back Propagation Neural Network (BPNN) controller based autonomous beam ...
T. Pasupathi, J. Arputha Vijaya Selvi
doaj  

Beam wandering of femtosecond laser filament in air

open access: yesOptics Express, 2015
The spatial wandering of a femtosecond laser filament caused by the filament heating effect in air has been studied. An empirical formula has also been derived from the classical Karman turbulence model, which determines quantitatively the displacement of the beam center as a function of the propagation distance and the effective turbulence structure ...
Jing, Yang   +3 more
openaire   +2 more sources

Effects of Anisotropic Turbulent Ocean on Propagation of Asymmetric Bessel-Gaussian Beam

open access: yesIEEE Photonics Journal
Aiming at the propagation of asymmetric vortex beam, we investigate the spreading and wander characteristics of asymmetric Bessel-Gaussian beam in oceanic turbulence. Based on the cross-spectral density and Wigner distribution function of beam field, the
Lin Yu   +3 more
doaj   +1 more source

Propagation of Optical Coherence Vortex Lattices in Turbulent Atmosphere

open access: yesApplied Sciences, 2018
Propagation properties in the turbulence atmosphere of the optical coherence vortex lattices (OCVLs) are explored by the recently developed convolution approach. The evolution of spectral density distribution, the normalized M 2 -factor, and the
Yan Huang   +7 more
doaj   +1 more source

Investigation of the Propagation Characteristics of Double-Ring Perfect Vortex Beams in Atmospheric Turbulence

open access: yesPhotonics
Double-ring perfect vortex beams (DR–PVBs) have attracted increasing attention due to their unique characteristics of carrying independent information channels and exhibiting higher security and stability during propagation.
Xiang Xu   +3 more
doaj   +1 more source

Is an Apple an Orange? A Large Language Model Benchmark for Candidate Term Extraction and Subclass Decisions Against Upper Ontologies in Engineering and Materials Science

open access: yesAdvanced Engineering Materials, EarlyView.
Building machine‐readable vocabularies for materials science is slow, expert‐driven work. This study benchmarks 13 large language models on two of its first steps: finding candidate terms in engineering articles and deciding where they belong in a class hierarchy.
Thomas Bjarsch   +3 more
wiley   +1 more source

Quantifying Subsurface Weak in‐Plane Magnetization of Mixed Phase BiFeO3 by Scanning Nitrogen Vacancy Magnetometry

open access: yesAdvanced Functional Materials, EarlyView.
We use scanning nitrogen vacancy magnetometry to directly image the weak in‐plane magnetic moments in mixed phase BiFeO3 at the nanoscale and quantify the local magnetic moments to be 18.8±2.0 μB/nm2 in the rhombohedral‐like phase and 1.5±0.6 μB/nm2 in the well‐known non‐magnetic tetragonal‐like phase.
Lei Wang   +14 more
wiley   +1 more source

Advances in Sustainable and Wearable Textile Based Soft Robotics

open access: yesAdvanced Functional Materials, EarlyView.
This Review examines advances in wearable textile‐based soft robotics, focusing on sustainable materials, integrated sensing, and scalable actuation. It discusses manufacturing and system integration across healthcare, assistive robotics, prosthetics, and human–machine interfaces, and highlights key challenges in circular design, including life‐cycle ...
Zahir Abbas   +6 more
wiley   +1 more source

Tuning the Optoelectronic Properties of Wide Bandgap Perovskites: Data‐Driven Insights from Combinatorial Synthesis and High‐Throughput Experimentation

open access: yesAdvanced Functional Materials, EarlyView.
Combinatorial vapor deposition enables independent tuning of Cs/Pb and Br/Cl in wide‐bandgap perovskites. Automated multimodal mapping of 500+ compositions reveals a high‐energy optical transition that correlates with enhanced photoluminescence, defining a practical Cs/Pb window.
Alexander Wieczorek   +6 more
wiley   +1 more source

Study of Reducing Atmospheric Turbulence-Induced Beam Wander of a Twisted Electromagnetic Elliptical Vortex Beam

open access: yesPhotonics
We derive the analytical expressions for root-mean-square (rms) beam wander (BW) and relative BW of a twisted electromagnetic elliptical vortex (TEEV) beam propagating through non-Kolmogorov atmospheric turbulence with the help of the extended Huygens ...
Kai Huang   +3 more
doaj   +1 more source

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