Article
Engineering, Electrical & Electronic
Yong-Dan Kong, Xiang-Lin Chen, Qing-Xin Chu
Summary: The study systematically investigates the numerical stability and dispersion analysis of the extended 2-D finite-difference time-domain (2-D-FDTD) method. It analyzes three different passive linear lumped elements, namely resistor, inductor, and capacitor, as well as three different formulations of explicit, semi-implicit, and implicit schemes. The numerical stability is analyzed by utilizing the von Neumann technique and Jury criterion, which has not been previously reported. Theoretical results show the stability conditions for different elements and schemes, and the analysis of numerical dispersion based on the Norton equivalent circuit leads to interesting theoretical deductions.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Engineering, Multidisciplinary
Yanlong Zhang, Yanhui Zhou, Jiming Wu
Summary: This article investigates a 2D nonlinear time-fractional Rayleigh-Stokes problem using quadratic finite volume element schemes on triangular meshes. The Caputo fractional derivative is discretized through a specific formula, and a two step scheme is used to approximate the time first-order derivative. Results show that the L-2 error estimate of one scheme is O(h(3) + Δt(2)), while others are O(h(2) + Δt(2)), indicating varying levels of accuracy.
CMES-COMPUTER MODELING IN ENGINEERING & SCIENCES
(2021)
Article
Mathematics, Applied
Chuanjun Chen, Yuzhi Lou, Hanzhang Hu
Summary: In this paper, a backward Euler full-discrete two-grid finite volume element scheme is proposed for solving time-dependent Schrodinger equation. By combining coarse grid and fine grid discretization, the method solves the coupled problem and independent Poisson problems simultaneously, improving the computational efficiency and ensuring accuracy.
COMPUTERS & MATHEMATICS WITH APPLICATIONS
(2022)
Article
Mathematics, Applied
Guofang Chen, Junliang Lv, Xinye Zhang
Summary: This paper solves a second-order nonlinear elliptic equation using the finite volume element method and provides rigorous error estimates. The computational domain is divided into convex quadrilateral meshes. The isoparametric bilinear element space is chosen as the trial function space and the piecewise constant function space is chosen as the test function space. The boundedness and coercivity of the bilinear form are proved on the h(2)-parallelogram mesh, and the existence and uniqueness of the numerical solution are established using the Brouwer fixed point theorem. The paper also derives estimates for parallel to(del(u-u(h))parallel to and parallel to u-u(h)parallel to(0) under certain regularity assumptions. Numerical experiments on quadrilateral meshes are conducted to calculate the convergence orders in H-1 and L-2 norms, which align with the theoretical results.
COMPUTERS & MATHEMATICS WITH APPLICATIONS
(2023)
Article
Mathematics, Applied
Yulong Gao, Yonghai Li, Guangwei Yuan, Zhiqiang Sheng
Summary: This paper develops new finite volume element methods in the ALE framework for time-dependent convection-diffusion problems on moving domains. Two fully discrete schemes are presented with stability and error estimation analysis, showing that the scheme satisfying the geometric conservation laws demonstrates better stability for long time simulations. Numerical experiments are conducted to illustrate the theoretical results.
JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
(2021)
Article
Mathematics, Applied
Han Zhou, Wenyi Tian
Summary: In this work, two efficient time-stepping schemes are proposed for solving sub-diffusion equations with mildly singular source terms in time. The proposed methods are rigorously analyzed for accuracy and verified through numerical investigations.
JOURNAL OF SCIENTIFIC COMPUTING
(2022)
Article
Engineering, Electrical & Electronic
Jiaxuan Wang, Qiang Ren
Summary: In this article, a 3-D hybrid ME-FDTD/WE-FETD method is proposed, which utilizes the wave equation-based finite-element time-domain method. The method combines different regions and employs different time integration schemes to improve efficiency and reduce calculation time. Numerical examples demonstrate the accuracy and improved efficiency of the proposed method compared to other existing methods.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Engineering, Electrical & Electronic
Xuejiao Zhao, Shipeng Wang, Qiong Wu, Yanju Ji
Summary: The theory of magnetic-source electromagnetic anomalous diffusion is developed, presenting a multiscale electromagnetic anomalous diffusion theory with improved generalized electrical conductivity. This theory is applied to propose a 3-D modeling method for complex electromagnetic propagation in rough geologic medium, demonstrating improved efficiency and accuracy in detection.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Mathematics, Applied
Huoyuan Duan, Qiuyu Zhang
Summary: This paper proposes and analyzes a residual-based a posteriori error estimator for a new finite element method for solving the time-dependent Ginzburg-Landau equations with the temporal gauge of superconductivity. The reliability of the error estimator is proven using the dual problem of a linearization of the original problem, and an adaptive algorithm with temporal and spatial refining and coarsening steps is proposed. Numerical results illustrate the performance of the error estimator and the adaptive algorithm in convex and nonconvex domains.
JOURNAL OF SCIENTIFIC COMPUTING
(2022)
Article
Engineering, Electrical & Electronic
Harune Sekido, Takayuki Umeda
Summary: This paper proposes a new explicit and non-dissipative finite-difference time-domain (FDTD) method in two and three dimensions for tackling the Courant condition. By adding third-degree spatial difference terms with coefficients to the time-development equations of FDTD(2,4), optimal coefficients are obtained through a brute-force search of the dispersion relations to reduce phase velocity errors while maintaining numerical stability. The new method is stable with large Courant numbers and exhibits smaller numerical errors in phase velocity compared to conventional FDTD methods with small Courant numbers.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Engineering, Electrical & Electronic
Rodrigo M. S. de Oliveira, Rodrigo R. Paiva
Summary: A central least-squares spatial derivative procedure and LS-FDTD method have been developed to approximate spatial derivatives and attenuate nonphysical modes. The proposed method has been successfully validated for 1-D and 2-D problems with time steps beyond the FDTD CFL limit, demonstrating accuracy and stability conditions for LS-FDTD.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Mathematics, Applied
Yihui Zeng, Zhendong Luo
Summary: This paper mainly establishes the CN mixed finite element method for the system of time-domain Maxwell's equations with a lossy medium, and conducts theoretical derivation, format construction, and stability analysis, while verifying the correctness of theoretical results through numerical tests.
APPLIED MATHEMATICS AND COMPUTATION
(2022)
Article
Mathematics
Mengya Su, Liuqing Xie, Zhiyue Zhang
Summary: In this study, an optimal control problem governed by elliptic PDEs with Dirichlet boundary conditions on complex connected domains is investigated. The convergence result for two-dimensional Dirichlet boundary control is proven using the Fourier finite volume element method. The Lagrange multiplier approach is employed to find the optimality systems of the Dirichlet boundary optimal control problem. The discrete optimal control problem is then obtained using the Fourier finite volume element method, reducing the original two-dimensional problem to a sequence of one-dimensional problems.
Article
Chemistry, Analytical
Negin Foroughimehr, Zoltan Vilagosh, Ali Yavari, Andrew Wood
Summary: This study used a mathematical simulation to investigate the absorption of millimeter wave (mmW) and terahertz (THz) waves by the cornea under normal and pathological conditions. Factors such as tear film thickness and hydration levels were considered, which are important for corneal health. The study found that changes in tear film properties, associated with dry eye syndrome, directly impact the absorption of mmW and THz waves by the cornea.
Article
Mathematics, Applied
Yunqing Huang, Jichun Li, Xuancen Yi, Haoke Zhao
Summary: In this paper, a finite element method (FEM) is developed and analyzed for the Drude perfectly matched layer (PML) model. The stability analysis and error estimate for the scheme are established. Numerical results demonstrate the effectiveness of this PML in absorbing outgoing waves in the Drude metamaterial.
JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
(2024)
Article
Optics
Yupei Wang, Jian Wei You, Zhihao Lan, Nicolae C. Panoiu
Article
Optics
Qun Ren, Feng Feng, Xiang Yao, Quan Xu, Ming Xin, Zhihao Lan, Jianwei You, Xiaofei Xiao, Wei E. Sha
Summary: This study introduces a wavelength-multiplexed nonlinear plasmon-MoS2 hybrid metasurface with suppression phenomenon, capable of processing multiple signals simultaneously. It presents a clear physical picture of nonlinear plasmonic bound states in the continuum (BICs) from both classical and quantum perspectives, demonstrating a giant BIC-inspired second-order nonlinear susceptibility of MoS2 in the infrared band.
Article
Engineering, Electrical & Electronic
Fengxia Li, Haiyan Chen, Yang Zhou, Jianwei You, Nicolae C. Panoiu, Peiheng Zhou, Longjiang Deng
Summary: A novel polarized reflectarray is designed and characterized for controlling wave generation and focusing of orbital angular momentum (OAM) vortices in the microwave frequency regime. The reflectarray can significantly reduce beam diameter and improve transmission efficiency of the OAM vortex beams, showing good agreement between numerical and experimental results. The proposed design method and reflectarrays may lead to new efficient approaches for generating and focusing OAM vortex waves in microwave wireless communications applications.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2021)
Article
Optics
Ivan Sekulic, Jian Wei You, Nicolae C. Panoiu
Summary: This article presents a T-matrix method for numerical computation of second-harmonic generation from clusters of arbitrarily distributed spherical particles made of centrosymmetric optical materials. By taking into account both local surface and nonlocal bulk polarization sources when computing the SH fields, our method accurately describes the generation of SH in arbitrary clusters of spherical particles. The numerical method can efficiently analyze clusters of spherical particles made of various optical materials.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2021)
Article
Optics
Z. Zhang, J. W. You, Z. Lan, N. C. Panoiu
Summary: Surface lattice modes generated by evanescent coupling in a 2D array of optical resonators exhibit optical response beyond single photonic particles. By employing the lattice mode concept, lattice topological edge and corner modes can be achieved in properly designed photonic crystal slabs, showing non-degenerate eigenfrequencies and dispersive bands in the topological band gap. Further tuning of optical coupling can shift the eigenfrequency of lattice topological modes, with potential applications in topological lasing and slow-light effects.
Article
Multidisciplinary Sciences
Jian Wei You, Qian Ma, Zhihao Lan, Qiang Xiao, Nicolae C. Panoiu, Tie Jun Cui
Summary: Topological photonics has revolutionized the manipulation of light by proposing a reprogrammable plasmonic topological insulator, which allows for ultrafast switching between different configurations using electric switches. This technology offers a versatile platform for integrating multiple photonic topological functionalities and is fabricated using printed circuit board technology for compatibility with integrated photoelectric systems.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Fluids & Plasmas
Guoda Xie, Zhixiang Huang, Jian Wei You, Zhihao Lan, Nicolae C. Panoiu, Wei E. I. Sha
Summary: The study focuses on the numerical solution of a general electromagnetic system using a formalism based on the E-B-A-phi formulas with different gauge conditions, and utilizes the FDTD method for discretization. The incorporation of the CPML technique successfully absorbs outgoing scattered waves and demonstrates the gauge invariance of EM fields in an inhomogeneous environment through numerical examples. Additionally, the integration of the proposed EM framework with the Schrodinger equation is introduced to investigate mesoscopic phenomena for light-matter interaction and design laser pulses for controlling discrete quantum states.
IEEE TRANSACTIONS ON PLASMA SCIENCE
(2021)
Review
Optics
Jian Wei You, Zhihao Lan, Qian Ma, Zhen Gao, Yihao Yang, Fei Gao, Meng Xiao, Tie Jun Cui
Summary: Metasurfaces are thin films with subwavelength structures that can control the polarization, phase, and amplitude of light. Recent developments in topological photonics have greatly expanded the design possibilities for metasurfaces in novel applications. This review summarizes recent progress in the field of topological metasurfaces, covering both passive and active systems in the classical and quantum regimes. It discusses passive topological phenomena and cutting-edge studies of active topological metasurfaces, as well as their potential applications in quantum information and many-body physics.
PHOTONICS RESEARCH
(2023)
Article
Computer Science, Information Systems
Zhuochen Lou, Xiongwei Wu, Junming Hou, Jianan Zhang, Jianwei You, Tiejun Cui
Summary: Developing numerical methods for dynamic electromagnetic problems has great potential for applications. Traditional numerical methods are not suitable for modeling time-varying materials and moving objects. In this paper, a numerical method called the time-domain finite integration technique (TDFIT) is extended to solve this problem by introducing time-varying iterative coefficients. Three numerical examples are presented to validate the effectiveness of the proposed algorithm.
Article
Optics
Yupei Wang, Jian Wei You, Nicolae C. Panoiu
Summary: We show that the Kerr effect on valley-Hall topological transport in graphene metasurfaces can be utilized to achieve an all-optical switch. By utilizing the high Kerr coefficient of graphene, the refractive index of the topologically-protected metasurface can be tuned by a pump beam, resulting in an optically controllable frequency shift of the photonic bands. This spectral variation enables the control and switching of optical signals in specific waveguide modes of the graphene metasurface. The dependence of the threshold pump power on the group velocity of the pump mode, especially in the slow-light regime, is crucial for the optical switching.
Proceedings Paper
Engineering, Electrical & Electronic
Y. Wang, J. W. You, Z. Lan, N. C. Panoiu
Summary: This study demonstrates topologically-protected plasmon transport in graphene-based plasmonic crystal waveguides and proposes designs for optically and chemically controllable nanodevices.
2022 PHOTONICS & ELECTROMAGNETICS RESEARCH SYMPOSIUM (PIERS 2022)
(2022)
Article
Optics
Xiuyu Wang, Jihong Xin, Qun Ren, Haocheng Cai, Jiaqi Han, Chengyi Tian, Pengcheng Zhang, Lijie Jiang, Zhihao Lan, Jianwei You, Wei E. Sha
Summary: Plasmonics offers compact and powerful solutions for nanophotonic technologies but the effective area of enhanced localized field is limited by structural boundaries. This work presents a method to generate high quality-factor extended electromagnetic fields on graphene metasurfaces by hybridizing the superradiant state and the quasi bound state in the continuum, which holds great promise for developing nanodevices with high sensing capacity in two dimensions.
CHINESE OPTICS LETTERS
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
J. T. Wang, J. W. You, Nicolae C. Panoiu
Summary: The integration of a nonlinear metasurface with monolayer MoS2 has led to a significant enhancement of second-harmonic generation (SHG) through the utilization of bound states in the continuum. The resonant metasurface achieved about 600 times SHG enhancement compared to suspended monolayer MoS2, and analytical results obtained through an eigen-mode expansion approach were found to agree well with rigorous calculations.
2021 FIFTEENTH INTERNATIONAL CONGRESS ON ARTIFICIAL MATERIALS FOR NOVEL WAVE PHENOMENA (METAMATERIALS)
(2021)
Proceedings Paper
Engineering, Electrical & Electronic
Yupei Wang, J. W. You, Nicolae C. Panoiu
Summary: The study focuses on the influence of graphene Kerr effect on valley-Hall topological modes in a graphene plasmonic crystal waveguide. By introducing extra air holes to break the spatial-inversion symmetry, a gapless Dirac cone and topologically protected edge modes are formed, allowing for the implementation of an all-optical switch in the system. This research could potentially lead to new graphene-based active topological photonic nanodevices.
2021 FIFTEENTH INTERNATIONAL CONGRESS ON ARTIFICIAL MATERIALS FOR NOVEL WAVE PHENOMENA (METAMATERIALS)
(2021)
Article
Optics
Zhihao Lan, Jian Wei You, Qun Ren, Wei E. Sha, Nicolae C. Panoiu
Summary: This research explores a new area of nonlinear topological photonics by demonstrating second-harmonic generation in all-dielectric photonic crystals through the nonlinear interaction of double topological valley-Hall kink modes. The study shows that tunable, bidirectional phase-matched SHG can be achieved through the nonlinear interaction of valley-Hall kink modes within the two frequency band gaps between two PhCs.
