Article
Materials Science, Multidisciplinary
Weiwei Su, Zhiyu Lin, Chunyan Li, Changming Huang
Summary: The study reveals the existence of different families of nonlinear localized modes supported by the width-modulated Fibonacci lattices, with one family originating from the upper band-edge linear mode. These gap modes are mostly stable throughout their existence domain, except for a small region in the middle. Additionally, two other families of nonlinear modes localized in the relatively large gap are found to be pure nonlinear modes, with a narrow stable region near their upper cutoff. The results of linear stability analysis are consistent with propagation simulations.
RESULTS IN PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Weiwei Su, Zhiyu Lin, Chunyan Li, Changming Huang
Summary: This article addresses the properties of nonlinear localized gap modes supported by width-modulated Fibonacci lattices, including their existence and stability. The study finds the existence of different families of nonlinear localized modes in two relatively large gaps, with one originating from linear modes and the other two being pure nonlinear modes.
RESULTS IN PHYSICS
(2022)
Article
Physics, Fluids & Plasmas
B. L. Kim, C. Chong, S. Hajarolasvadi, Y. Wang, C. Daraio
Summary: In this study, the response of a one-dimensional phononic lattice with time-periodic elastic properties is investigated in both linear and nonlinear regimes using experimental, numerical and theoretical approaches. It is found that wave-number band gaps emerge under small-amplitude excitation, while large-amplitude responses are stabilized via the nonlinear nature of the magnetic interactions, resulting in a family of nonlinear time-periodic states. Controlling acoustic and elastic wave propagation by balancing nonlinearity and external modulation offers potential applications in signal processing and telecommunication devices.
Article
Engineering, Electrical & Electronic
Steffen Kuhn
Summary: Weber-Maxwell electrodynamics combines classical Weber electrodynamics and Maxwell's equations into a single 3-D wave equation. It inherits properties from both theories, such as the absence of the concept of magnetic field and the satisfaction of Newton's third law from Weber electrodynamics, and compatibility with electromagnetic waves from Maxwell's electrodynamics.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Engineering, Electrical & Electronic
Hao Qin, Xingqi Zhang
Summary: This letter proposes an efficient split-step parabolic equation-based model using sparse Fourier transform techniques, which significantly accelerates wave propagation modeling in tunnels. The accuracy and efficiency of the proposed model are demonstrated through comparison with experimental measurements and simulation models in actual tunnel cases.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Maxim S. Masyukov, Alexander N. Grebenchukov
Summary: This study investigates time-varying metamaterials based on graphene layers, demonstrating frequency variation of scattered waves due to rapid Fermi level switching. Results show that as the Fermi level increases rapidly, the frequency of scattered waves also increases.
Article
Geochemistry & Geophysics
Lin Zhang, Jing Ba, Jose M. Carcione
Summary: The theory developed in this study describes wave propagation in porous media with inclusions at multiple scales, derived from differential effective medium theory and Biot-Rayleigh theory for double-porosity media. The theory determines generalized stiffness and density coefficients based on the first principles of strain, kinetic, and dissipation energies, showing that anelasticity depends on various factors such as inclusion size, distribution parameter, mean radius, and variance. Experimental results confirm the model's validity in describing anelasticity observed in laboratory and field measurements.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Physics, Applied
Janghoon Kang, Michael R. Haberman
Summary: This article investigates the spatiotemporal modulation of the surface acoustic admittance of a metasurface diffuser to improve sound diffusion. By using mathematical and finite element models, it demonstrates that the effects of spatial periodicity can be mitigated without introducing aperiodic spacing, thus reducing diffuser thickness and improving the diffusivity of the backscattered field.
APPLIED PHYSICS LETTERS
(2022)
Article
Mathematics, Applied
Davor Dragicevic
Summary: This note formulates sufficient conditions for certain class of second order nonlinear and nonautonomous differential equations to be Hyers-Ulam stable, which are obtained by perturbing Hill's equation.
RESULTS IN MATHEMATICS
(2021)
Article
Physics, Applied
Noah Kruss, Jayson Paulose
Summary: This study presents a mechanism for one-way amplification of sound waves across an entire frequency band using spacetime-periodic modulation of local stiffnesses. By modulating the local parameters in the active metamaterials, the forward-propagating acoustic band modes can be amplified while no amplification occurs in the reverse-propagating band. The amplification is nearly uniform across the lowest-frequency band, enabling amplification of wave packets while preserving their speed, shape, and spectral content.
PHYSICAL REVIEW APPLIED
(2022)
Article
Acoustics
Liang Xu, Haigang Zhang, Minghui Zhang
Summary: This paper introduces the use of Deep Operator Networks (DeepONets) to approximate the parabolic equations (PEs) in modeling sound propagation. By training the network, it can predict the far field for different environmental conditions at a lower computational cost, achieving high accuracy.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2023)
Article
Engineering, Environmental
Fei Sun, Qingdong Liu, Yifeng Xu, Xipeng Xin, Zezhen Wang, Xuefeng Song, Xiaofeng Zhao, Jijin Xu, Jing Liu, Liping Zhao, Peng Zhang, Lian Gao
Summary: The study focuses on developing electromagnetic wave absorption materials (EAMs) to mitigate the harm caused by the extensive use of electromagnetic waves. A novel attapulgite-modulated thorny nickel nanowires/graphene aerogel was fabricated with excellent absorption performance through a simple manufacturing process.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Optics
Xianwei Huang, Wei Tan, Teng Jiang, Suqin Nan, Yanfeng Bai, Xiquan Fu
Summary: The propagation of modulated vortex beams in nonlocal media is investigated numerically. The beam exhibits splitting characteristics and generates multiple beam spots in free space. In nonlocal media, the propagation of modulated vortex beams generates multiple solitons, and the behavior of solitons depends on the nonlocality and initial amplitude. Unlike unmodulated vortex beams, the number of solitons can be controlled through azimuthal vortex modulation. By adjusting the nonlocality and vortex modulation parameters, a linear relationship between the number of solitons and modulation phase folds is analyzed. This type of vortex beam has potential applications in optical controlling.
OPTICS COMMUNICATIONS
(2023)
Article
Optics
Ke Li, Jingping Zhu, Qihang Duan, Yuzhou Sun, Xun Hou
Summary: The first ultra-broadband Bragg concave diffraction grating on a 220-nm silicon-on-insulator is presented, covering most telecommunication wavebands. Numerical simulations and design verification demonstrate the high performance of the grating in wavelength demultiplexing.
Article
Multidisciplinary Sciences
Jose Luis Paz, Patricio J. Espinoza-Montero, Marcos Lorono, Fernando Javier Torres, Lenin Gonzalez-Paz, Edgar Marquez, Joan Vera-Villalobos, Jose R. Mora, Fernando Moncada, Ysaias J. Alvarado
Summary: We studied the relationship between the four-wave mixing (FWM) signal and the pump power in an aqueous solution of Malachite green, and reproduced the characteristics of the nonlinear signal by a theoretical model. The effects of intramolecular coupling and signal propagation on the nonlinear intensity were investigated. Our calculation scheme considers both the intramolecular coupling effects and the effects produced by the propagation of the FWM signal, resulting in an exponential dependence on the intensity of the pumping beam.
Article
Physics, Multidisciplinary
Corentin Coulais, Romain Fleury, Jasper van Wezel
Summary: Topology and symmetry are crucial guiding principles in predicting and harnessing wave propagation in natural and artificial materials. Recent explorations have focused on non-conservative, non-equilibrium, and non-Hermitian systems, leading to significant implications for physics and engineering disciplines.
Article
Chemistry, Multidisciplinary
Rayehe Karimi Mahabadi, Taha Goudarzi, Romain Fleury, Reza Naghdabadi
Summary: By leveraging the hyperelastic behavior, the HSS demonstrated an 8% shift in resonance frequency within the GHz range, and more than 40 dB increase/decrease in the scattering parameter S-21 from largely transparent to opaque. Experimental tests and numerical simulations validated the multiphysics functionalities of the HSS.
APPLIED SCIENCES-BASEL
(2021)
Article
Physics, Applied
Ali Momeni, Mahdi Safari, Ali Abdolali, Nazir P. Kherani, Romain Fleury
Summary: A novel bianisotropic meta-atom structure allows advanced control of electric, magnetic, and magnetoelectric resonances with high geometric freedom and tunability in frequency and strength of resonances. This structure shows potential for various applications at both microscopic and macroscopic levels, including electric dipole-free and zero scattering capabilities.
PHYSICAL REVIEW APPLIED
(2021)
Article
Chemistry, Physical
Ali Momeni, Kasra Rouhi, Romain Fleury
Summary: This paper presents reconfigurable graphene-based multilayers for spatiotemporal analog signal and image processing, demonstrating a switchable analog computing paradigm and simultaneous parallel spatiotemporal analog computing. The spatial-and temporal-frequency responses are engineered for integrated functionalities by selecting a proper external voltage for graphene monolayers, showing promising developments in analog computing.
Article
Multidisciplinary Sciences
Ali Momeni, Romain Fleury
Summary: This article introduces an analog neuromorphic platform for optical wave-based machine learning, which is characterized by energy efficiency, speed, and scalability. By utilizing time-Floquet physics to induce strong non-linear entanglement between signal inputs at different frequencies, the authors successfully solve complex neuromorphic computing tasks.
NATURE COMMUNICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Farzad Zangeneh Nejad, Romain Fleury
Summary: An important advantage of optical signal processing is its ability to perform various operations in parallel. Frequency division multiplexing (FDM) is a well-known technique for parallel optical signal processing, where different operations are performed in multiple sub-channels associated with different frequency bands. In this study, we demonstrate the possibility of performing parallel optical signal processing by frequency division multiplexing the edge modes of a topological photonic structure. This leads to the realization of a multiple-input-multiple-output (MIMO) topological optical signal processor that can perform several analog functionalities simultaneously, significantly enhancing computation speed. Our theoretical and experimental findings open up new avenues for the realization of a new generation of multi-functional topological optical signal processing systems that are ultra-fast, consume little power, and have strong protection against disorder.
IEEE PHOTONICS TECHNOLOGY LETTERS
(2023)
Article
Optics
Omid Tahmasebi, Ali Abdolali, Hamid Rajabalipanah, Ali Momeni, Romain Fleury
Summary: This paper proposes a polarization-multiplexed graphene-based metasurface that can perform distinct mathematical operations on parallel time-domain channels enabled by vertical and horizontal polarizations. The metasurface is composed of perpendicularly-oriented graphene strips with dynamically tunable chemical potential. It enables real-time parallel temporal analog computing and has potential applications in terahertz spectroscopy architectures, communication systems, and computing technologies.
Article
Physics, Multidisciplinary
Aleksi Bossart, Romain Fleury
Summary: To date, most architected materials use the principles of Bragg interference and local resonances to control wave behavior. This paper introduces a third approach: structures that have a finite number of delocalized zero-energy modes, resulting in anomalous dispersion cones that arise from extreme spatial dispersion at 0 Hz. The authors demonstrate how to design such zero-energy modes in elastic systems, and show that these structures can exhibit many of the unique wave properties of metamaterials at subwavelength scales, without the same bandwidth limitations. The theory is validated through simulations and experiments, and an inverse design method is presented to create anomalous cones at desired locations in k space.
PHYSICAL REVIEW LETTERS
(2023)
Article
Multidisciplinary Sciences
Stanislav Sergeev, Romain Fleury, Herve Lissek
Summary: Controlling audible sound requires broadband and subwavelength acoustic solutions, which are currently not available. This paper introduces the concept of plasmacoustic metalayers to solve this problem, demonstrating that small layers of air plasma can interact with sound in an ultrabroadband manner over deep-subwavelength distances. By exploiting the unique physics of plasmacoustic metalayers, perfect sound absorption and tunable acoustic reflection can be achieved over a wide frequency range, from several Hz to the kHz range, using transparent plasma layers with thicknesses down to lambda/1000. This bandwidth and compactness are essential for various applications including noise control, audio engineering, room acoustics, imaging, and metamaterial design.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Applied
Matthieu Mallejac, Romain Fleury
Summary: This paper presents a general extension of transmission-line or telegraph equations to periodically time-modulated systems and obtains a general approach to compute and measure the complete scattering matrix of such systems. The proposed theory and methods are applied and validated on a concrete practical example in the realm of airborne acoustics.
PHYSICAL REVIEW APPLIED
(2023)
Article
Multidisciplinary Sciences
Zhe Zhang, Pierre Delplace, Romain Fleury
Summary: Topological insulators are crystalline materials that allow for unidirectional wave transport immune to obstacles and local disorder. However, they break down in the presence of high disorder, transitioning to a trivial insulating phase. In this study, we demonstrate a 2D amorphous topological regime that survives strong levels of amorphism, enabling unidirectional edge transport in a nonreciprocal scattering network.
Article
Physics, Multidisciplinary
Xinxin Guo, Herve Lissek, Romain Fleury
Summary: Researchers achieved large breaking of reciprocity in sound transmission by using non-Hermitian physics, allowing for non-symmetric transmission of sounds composed of multiple harmonics while preserving their timbre.
COMMUNICATIONS PHYSICS
(2023)
Article
Instruments & Instrumentation
Janez Rus, Romain Fleury
Summary: We propose a reconfigurable medium based on a shape memory polymer for manipulating the elastic propagation properties of Lamb waves. By using a laser pulse to excite waves and a laser vibrometer for detection, we control a two-dimensional temperature field with a scanning heating laser. Genetic algorithms are employed to optimize the mechanical properties distribution for maximizing the wave amplitude at a specific location and minimizing it at one or two other locations. The reconfigurability of the medium allows for direct optimization on the object of interest, leading to improved wave propagation.
SMART MATERIALS AND STRUCTURES
(2023)
Article
Physics, Applied
Mathieu Padlewski, Maxime Volery, Romain Fleury, Herve Lissek, Xinxin Guo
Summary: This paper presents an acoustic dimer composed of two electronically controlled electroacoustic resonators to explore one-dimensional topological phenomena. Active control allows manipulation of the metamaterial's properties, enabling tunable topological phase transitions. The paper provides an analytical model and electronic control scheme, and demonstrates the realization of a tunable one-dimensional topological insulator through consistent band structure analysis from the analytical model, finite-element simulation, and experimental data.
PHYSICAL REVIEW APPLIED
(2023)
Article
Nanoscience & Nanotechnology
Hamid Rajabalipanah, Ali Momeni, Mahdi Rahmanzadeh, Ali Abdolali, Romain Fleury
Summary: This paper proposes a multi-functional metagrating that modulates both spatial and angular properties of the input signal, thereby achieving symmetric and asymmetric optical transfer functions. The performance of the designed compound metallic grating is validated through several investigations, and several examples are demonstrated to illustrate its application in analog computing tasks.
