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arXiv 2022年

作者： Tay, Fuyang Lin, Xiao Shi, Xihang Chen, Hongsheng Kaminer, Ido Zhang, Baile Interdisciplinary Center for Quantum Information State Key Laboratory of Modern Optical Instrumentation ZJUHangzhou Global Science and Technology Innovation Center College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Applied Physics Graduate Program Smalley–Curl Institute Rice University HoustonTX77005 United States International Joint Innovation Center The Electromagnetics Academy Zhejiang University Zhejiang University Haining314400 China Department of Electrical Engineering Technion-Israel Institute of Technology Haifa32000 Israel Jinhua Institute of Zhejiang University Zhejiang University Jinhua321099 China Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University 637371 Singapore Centre for Disruptive Photonic Technologies Nanyang Technological University 637371 Singapore

Free-electron radiation is a fundamental photon emission process that is induced by fast-moving electrons interacting with optical media. Historically, it has been understood that, just like any other photon emission process, free-electron radiation must be constrained within a finite time interval known as the "formation time", whose concept is applicable to both Cherenkov radiation and transition radiation, the two basic mechanisms describing radiation from a bulk medium and from an interface, respectively. Here we reveal an alternative mechanism of free-electron radiation far beyond the previously defined formation time. It occurs when a fast electron crosses the interface between vacuum and a plasmonic medium supporting bulk plasmons. While emitted continuously from the crossing point on the interface — thus consistent with the features of transition radiation — the extra radiation beyond the conventional formation time is supported by a long tail of bulk plasmons following the electron’s trajectory deep into the plasmonic medium. Such a plasmonic tail mixes surface and bulk effects, and provides a sustained channel for electron-interface interaction. These results also settle the historical debate in Ferrell radiation, regarding whether it is a surface or bulk effect, from transition radiation or plasmonic oscillation. Copyright © 2022, The Authors. All rights reserved.

关键词： Plasmonics

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Reliable Collaborative Semi-infrastructure Vehicle-to-Vehicle Communication for Local File Sharing 15th

Reliable Collaborative Semi-infrastructure Vehicle-to-Vehicl...

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15th EAI International Conference on Collaborative Computing: Networking, Applications and Worksharing, CollaborateCom 2019

作者： Mokhtar, Bassem Azab, Mohamed Fathalla, Efat Ghourab, Esraa M. Magdy, Mohamed Eltoweissy, Mohamed Electrical Engineering Department Alexandria University Alexandria Egypt Computer Engineering Program School of Engineering and Applied Sciences Nile University Giza Egypt Computer and Information Sciences Virginia Military Institute LexingtonVA24450 United States Department of Electrical and Computer Engineering Old Dominion University NorfolkVA United States College of Computing and Information Technology Arab Academy for Science Technology and Maritime Transport Alexandria Egypt

ISBN: (纸本)9783030301453

Recently, Vehicular Cloud Communication (VCC) has been gaining momentum targeting intelligent and efficient data transmission. VCC is a type of mobile ad-hoc network comprising heterogeneous vehicles sharing their resources to perform collaborative activities. In this paper, we propose a new semi-infrastructure file-browsing in order to provide Network as a service (NaaS) enabling internet-independent browsing. In our scenario, a central management platform plays the role of controlling and managing the selection of relaying vehicles supporting the source to destination file transmission procedure. Nagel-Schreckenberg rules for traffic cellular automata (CA) are used as the basis for our scenario simulation. Nagel-Schreckenberg rules simulate the behavior of a group of hypothetical vehicles moving across a highway. We study the reliability and efficiency of file transfer in such settings. Simulation results show that the number of selected relays required to establish the network highly impacts the probability of successfully sending the requested files. In addition, the distances between the selected relays influence the network throughput and the probability of network failure. Moreover, the density of relays strongly affects the overall delay that occurs due to the continuous re-transmission of the selected files among different hops. © 2019, ICST Institute for computer sciences, Social Informatics and Telecommunications engineering.

关键词： Vehicle to vehicle communications

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Efficient Focusing with Large Numerical Aperture Using a Hybrid Metalens

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Physical Review Applied 2020年第4期13卷 044016-044016页

作者： Ming Kang Younes Ra'di Diego Farfan Andrea Alù Department of Electrical and Computer Engineering The University of Texas at Austin Austin Texas 78712 USA Photonics Initiative Advanced Science Research Center City University of New York New York 10031 USA Physics Program Graduate Center City University of New York New York 10016 USA Department of Electrical Engineering City College of The City University of New York New York 10031 USA

Focusing light using electrically thin layers is of paramount importance in several applications, from integrated optics to microwave engineering and sensing. Recently, gradient metasurfaces, which are electrically thin arrays of densely located polarizable particles, have been employed to perform different wave-front transformations, including focusing. In comparison to a bulk lens, these designs provide ultrathin geometries, but they suffer from fundamental limitations on their overall efficiency and achievable numerical aperture. Metagratings offer a solution for efficient beam steering at large angles, but it is challenging to utilize them in the small-angle limit. Here, we introduce a hybrid metalens design, which provides dramatic enhancement in lensing performance compared with that of state-of-the-art metasurfaces, combining metagratings and conventional gradient approaches. Our experimental prototype enables microwave focusing with large efficiency (η=0.479) and near-unity numerical aperture (NA=0.98), yielding a sharp focal point at the diffraction limit in the far field (FWHM=0.332λ). We propose a hybrid metalens design with exceptional performance in terms of efficiency and numerical aperture, opening up opportunities for high-throughput optical lithography, high-density data recording, focal plane arrays, radar, and communication systems.

关键词： Classical optics Integrated optics Metamaterials Optical & microwave phenomena Devices Surfaces

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TextAI 3.0 (Multimodal): multimodal sentiment analysis using attention-enabled ensemble-based deep learning in hyperbolic space

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International Journal of Information Technology (Singapore) 2025年 1-16页

作者： Singh, Jaskaran Sanga, Prabhav Khanna, Narendra N. Laird, John R. Singh, Inder M. Kalra, Mannudeep K. Mantella, Laura E. Johri, Amer M. Faa, Gavino Tiwari, Ekta Singh, Rajesh Abbas, Mohamed Saba, Luca Suri, Jasjit S. Stroke Monitoring and Diagnostic Division AtheroPoint™ Roseville 95661 CA United States Bharati Vidyapeeth’s College of Engineering New Delhi India Department of Cardiology Indraprastha APOLLO Hospitals New Delhi 110001 India Department of Neurology and Stroke Program University of Maryland School of Medicine Baltimore United States Department of Radiology Harvard Medical School Boston 02115 MA United States Department of Biomedical and Molecular Sciences Queen’s University Kingston ON Canada Division of Cardiology Department of Medicine Queen’s University Kingston ON Canada Department of Pathology University of Cagliari Cagliari Italy Department of Computer Science Visvesvaraya National Institute of Technology (VNIT) Nagpur 440010 India Department of Research and Innovation Uttaranchal Institute of Technology Uttaranchal University Dehradun 248007 India Central Labs King Khalid University P.O. Box 960 AlQura’a Abha Saudi Arabia Electrical Engineering Department College of Engineering King Khalid University Abha 61421 Saudi Arabia Department of Neurology University of Cagliari Cagliari Italy Department of ECE Idaho State University Pocatello 83209 ID United States Department of CE Graphic Era Deemed to Be University Dehradun 248002 India University Center for Research and Development Chandigarh University Mohali India Symbiosis Institute of Technology Symbiosis International (Deemed University) Nagpur Campus Pune India Department of Innovation Global Biomedical Technologies Inc. Roseville 95661 CA United States

The rising prevalence of depression presents a significant global health challenge, underscoring the need for effective early detection through sentiment analysis. Traditional multimodal sentiment analysis methods, which rely on Euclidean space for data representation, often fail to capture the complex hierarchical relationships and non-linear structures inherent in multimodal data. To address this limitation, we propose a novel multimodal architecture that operates in hyperbolic space and incorporates attention-based ensemble learning to enhance feature representation and model performance. We developed and evaluated ten AI models—five utilizing Euclidean space and five leveraging hyperbolic space—on the Spoken Language Understanding Evaluation (SLUE) benchmark dataset. The models were assessed using cross-validation techniques to ensure robustness, and statistical analyses were conducted to validate the findings. Our results indicate that hyperbolic-based multimodal models achieve a 2.32% improvement in accuracy compared to their Euclidean counterparts, while the integration of self-attention mechanisms further contributes an average accuracy gain of 0.96%. Additionally, we observed a 3.76% decline in performance when reducing the training-to-test data ratio from 90:10 to 50:50, highlighting the importance of data distribution in model training. These findings confirm that attention-enhanced multimodal models in hyperbolic space offer superior representations for sentiment analysis. © Bharati Vidyapeeth's Institute of computer Applications and Management 2025.

关键词： Attention-enabled Deep learning Euclidean space Hyperbolic space Multimodal Sentiment analysis

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Depinning of the charge-density waves in Quasi-2D 1T-TaS2 devices operating at room temperature

arXiv

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arXiv 2021年

作者： Mohammadzadeh, A. Rehman, A. Kargar, F. Rumyantsev, S. Smulko, J.M. Knap, W. Lake, R.K. Balandin, Alexander A. Nano-Device Laboratory Department of Electrical and Computer Engineering Bourns College of Engineering University of California RiversideCA92521 United States CENTERA Laboratories Institute of High-Pressure Physics Polish Academy of Sciences Warsaw01-142 Poland Phonon Optimized Engineered Materials Center Materials Science and Engineering Program Bourns College of Engineering University of California RiversideCA92521 United States Department of Metrology and Optoelectronics Gdańsk University of Technology Gdańsk80-233 Poland Centre for Advanced Materials and Technologies CEZAMAT Warsaw University of Technology Warsaw02-822 Poland Laboratoire Charles Coulomb University of Montpellier and CNRS Montpellier34950 France Laboratory for Terascale and Terahertz Electronics Department of Electrical and Computer Engineering University of California RiversideCA92521 United States

We report on depinning of nearly-commensurate charge-density waves in 1T-TaS2 thin-films at room temperature. A combination of the differential current-voltage measurements with the low-frequency noise spectroscopy provide unambiguous means for detecting the depinning threshold field in quasi-2D materials. The depinning process in 1T-TaS2 is not accompanied by an observable abrupt increase in electric current – in striking contrast to depinning in the conventional charge-density-wave materials with quasi-1D crystal structure. We explained it by the fact that the current density from the charge-density waves in the 1T-TaS2 devices is orders of magnitude smaller than the current density of the free carriers available in the discommensuration network surrounding the commensurate charge-density-wave islands. The depinning fields in 1T-TaS2 thin-film devices are several orders of magnitude larger than those in quasi-1D van der Waals materials. Obtained results are important for the proposed applications of the charge-density-wave devices in electronics. Copyright © 2021, The Authors. All rights reserved.

关键词： Van der Waals forces

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THz Emission from Exchange-Coupled Fe/Ru/Ni Spintronic Emitters

THz Emission from Exchange-Coupled Fe/Ru/Ni Spintronic Emitt...

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International Conference on Infrared and Millimeter Waves

作者： R. Adam C. Greb D. E. Bürgler D. Cao S. Heidtfeld F. Wang J. Cheng D. Chakraborty I. Komissarov H. Hardtdegen M. Mikulics M. Büscher C. M. Schneider Roman Sobolewski Research Centre Jülich Peter Grünberg Institute (PGI-6) Jülich Germany Institut für Laser- und Plasmaphysik Heinrich Heine Universität Düsseldorf Düsseldorf Germany College of Physics Center for Marine Observation and Communications Qingdao University Qingdao China Materials Science Graduate Program University of Rochester Rochester New York USA Laboratory for Laser Energetics University of Rochester Rochester New York USA Department of Electrical and Computer Engineering University of Rochester Rochester New York USA Research Centre Jülich Ernst Ruska Centre for Microscopy and Spectroscopy with Electrons Jülich Germany Faculty of Physics University Duisburg-Essen Duisburg Germany Department of Physics University of California Davis Davis California USA

We explored THz emission from $\mathrm{Si}^{2} / \mathrm{SiO}_{2} / / \mathrm{Ta} / \mathrm{Fe} / \mathrm{Ru} /$ $\mathrm{Ni} / \mathrm{Al}_{2} \mathrm{O}_{3}$ spintronic emitters. We tuned magnetization alignment of Fe and Ni layers by varying the interlayer exchange coupling (IEC) strength using a range of Ru layer thickness t. Depending on IEC strength, magnetization hysteresis shows either ferromagnetic $(t=1.1 \mathrm{~nm}, 1.5 \mathrm{~nm})$, antiferromagnetic $(t=1.3 \mathrm{~nm})$ or canted $(t=1.7 \mathrm{~nm}, 1.9 \mathrm{~nm})$ relative alignment. Competition between IEC and an external magnetic field results in a dramatic difference in THz emission from the ferromagnetically (FM) and anti-ferromagnetically (AFM) coupled structures. The resulting THz emission from IEC structures is a result of an interference of THz transiens generated by the individual $\mathrm{Fe} / \mathrm{Ru}$ and $\mathrm{Ru} / \mathrm{Ni}$ emitters.

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Parity-time Symmetry Based on Time Modulation

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Physical Review Applied 2020年第3期14卷 031002-031002页

作者： Huanan Li Hady Moussa Dimitrios Sounas Andrea Alù Photonics Initiative Advanced Science Research Center City University of New York New York New York 10031 USA Department of Electrical Engineering City College of The City University of New York New York 10031 USA Department of Electrical and Computer Engineering Wayne State University Detroit Michigan 48202 USA Physics Program Graduate Center City University of New York New York New York 10016 USA

We leverage aperiodic temporal modulations and nonreciprocity to realize PT-symmetric phenomena without the need for gain and loss provided by external mechanisms. We develop our approach using a general coupled-mode framework, and verify our results via detailed simulations in a conservative electronic circuit, demonstrating wave phenomena such as scattering PT-phase transition and anisotropic transmission resonances in a Hermitian system. Our concept opens the possibility of implementing PT-symmetric phenomena without gain, with applications in sensing, communications, and a broad range of quantum physics.

关键词： Symmetry protected topological states Coupled oscillators Metamaterials PT-symmetry Cavity resonators Coupled mode theory S-matrix method in transport

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Marangoni convection-driven laser fountains and waves on free surfaces of liquids

arXiv

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arXiv 2021年

作者： Lin, Feng Quraishy, Aamir Nasir Tong, Tian Li, Runjia Yang, Guang Mohebinia, Mohammadjavad Qiu, Yi Vishal, Talari Zhao, Junyi Zhang, Wei Zhong, Hong Zhang, Hang Zhou, Chaofu Tong, Xin Yu, Peng Hu, Jonathan Dong, Suchuan Liu, Dong Wang, Zhiming Schaibley, John R. Bao, Jiming Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of China ChengduSichuan610054 China Department of Electrical and Computer Engineering University of Houston HoustonTX77204 United States Department of Physics University of Arizona TucsonAZ85721 United States James C. Wyant College of Optical Sciences University of Arizona TucsonAZ85721 United States Department of Mechanical Engineering University of Houston HoustonTX77204 United States Materials Science and Engineering Program University of Houston HoustonTX77204 United States School of Science Southwest Petroleum University ChengduSichuan610500 China Department of Electrical and Systems Engineering Washington University in St. Louis St. LouisMO63130 United States Department of Electrical & Computer Engineering Baylor University WacoTX76798 United States Department of Mathematics Purdue University West LafayetteIN47907 United States Department of Physics Texas Center for Superconductivity University of Houston HoustonTX77204 United States

It is well accepted that an outward Marangoni convection from a low surface tension region will make the surface depressed. Here, we report that this established perception is only valid for thin liquid films. Using surface laser heating, we show that in deep liquids a laser beam actually pulls up the fluid above the free surface generating fountains with different shapes. Whereas with decreasing liquid depth a transition from fountain to indentation with fountain-in-indentation is observed. Further, high-speed imaging reveals a transient surface process before steady elevation is formed, and this dynamic deformation is subsequently utilized to resonantly excite giant surface waves by a modulated laser beam. Computational fluid dynamics models reveal the underlying flow patterns and quantify the depth-dependent and time-resolved surface deformations. Our discoveries and techniques have upended the century-old perception and opened up a new regime of interdisciplinary research and applications of Marangoni-induced interface phenomena and optocapillary fluidic surfaces - the control of fluids with light. © 2021, CC BY.

关键词： Deformation

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TDDFT Studies on Sheet Size-Dependency of Optoelectronic Properties of 2D Silicon Doped with Alkali Metals

TDDFT Studies on Sheet Size-Dependency of Optoelectronic Pro...

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IEEE International Conference on Nano/Micro Engineered and Molecular Systems (NEMS)

作者： MD Raiyan Alam Muath Bani Salim Ganesh Alwarappan Aashka Bhandari Sunil Patil Sherin Alfalah Mohamed Shibl Walid Hassan Reza Nekovei Amit Verma Electrical Engineering and Computer Science Texas A&M University-Kingsville Kingsville TX Sustainable Energy Systems Engineering Program Texas A&M University-Kingsville Kingsville TX College of Engineering Pune Maharashtra India Gas Processing Center Qatar University Qatar College of Arts and Sciences Qatar University Doha Qatar Faculty of Science King Abdulaziz University Jeddah Saudi Arabia

ISBN: (数字)9781728172309

ISBN: (纸本)9781728172316

This work investigates the effect of alkali metals (Li, Na, and K) doping on silicene sheets (2D silicon) by using Time-Dependent Density Functional Theory (TDDFT). This includes Si 13 H 22 , Si 19 H 30 , Si 54 H 74 , and Si 104 H 134 silicene sheets. The results show some variation in the IR and UV-Vis spectrums as the sheet size change, with the largest structure showing an onset of absorption in the visible spectrum. Also, the results show that excitation energy decreases significantly by 29% as the number of atoms increases from Si 13 H 22 to Si 104 H 134 . Also, this work investigates the doping effect of alkali metals (Li, Na, and K) on the silicene sheets. The doped structures showed a dipole moment as high as approximately 10 Debye. The doped structures show a significant increase in optical absorption in the visible spectrum, as well as the potential for high reactivity.

关键词： Conferences

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Acoustic Supercoupling in a Zero-Compressibility Waveguide

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Research 2019年第1期2019卷 1086-1095页

作者： H.Esfahlani M.S.Byrne M.McDermott A.Alù Photonics Initiative Advanced Science Research CenterCity University of New YorkNew York CityNY 10031USA Department of Electrical and Computer Engineering Te University of Texas at AustinAustinTX 78712USA Electrical Engineering Institute Ecole Polytechnique Fed´erale de Lausanne(EPFL)CH-1015 LausanneSwitzerland Naval Surface Warfare Center Carderock Division West BethesdaMD 20817USA Physics Program Graduate CenterCity University of New YorkNew York CityNY 10026USA Department of Electrical Engineering City College of New YorkNew York CityNY 10031USA

Funneling acoustic waves through largely mismatched channels is of fundamental importance to tailor and transmit sound for a variety of *** electromagnetics,zero-permittivity metamaterials have been used to enhance the coupling of energy in and out of ultranarrow channels,based on a phenomenon known as *** metamaterial channels can support total transmission and complete phase uniformity,independent of the channel length,despite being geometrically mismatched with their input and output *** the feld of acoustics,this phenomenon is challenging to achieve,since it requires zero-density metamaterials,typically realized with waveguides periodically loaded with membranes or *** to electromagnetics,the additional challenge is due to the fact that conventional acoustic waveguides do not support a cut-of for the dominant mode of propagation,and therefore zero-index can be achieved only based on a collective resonance of the loading *** we propose and experimentally realize acoustic supercoupling in a dual regime,using a compressibility-nearzero acoustic *** than engineering the channel with subwavelength inclusions,we operate at the cut-of of a higherorder acoustic mode,demonstrating the realization and efcient excitation of a zero-compressibility waveguide with efective sof *** experimentally verify strong transmission through a largely mismatched channel and uniform phase distribution,independent of the channel *** results open interesting pathways towards the realization of extreme acoustic parameters and their implementation in relevant applications,such as ultrasound imaging,acoustic transduction and sensing,nondestructive evaluation,and sound communications.

关键词： waveguide coupling realization

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