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2024 IEEE International Conference on Computational Electromagnetics, ICCEM 2024

作者： Tserkezis, C. POLIMA-Center For Polariton-driven Light-Matter Interactions University of Southern Denmark Campusvej 55 Odense MDK-5230 Denmark

ISBN: (纸本)9798350383317

The surface-response formalism (SRF) embodied by the Feibelman d parameters offers a promising route for bridging the gap between the classical and quantum worlds in plasmonics. Without radically affecting the description of the system (typically one or more few-nm scatterers) in terms of Maxwell's equations and the bulk permittivity, SRF introduces effects of atomistic/solid-state origin via modification of the boundary conditions at the surface of the scatterer, and the inclusion of quantum effects through surface polarisation and current densities. Here we discuss the influence of these corrections on both the far-field spectra of the scatterers and on their coupling to quantum emitters. © 2024 IEEE.

关键词： Maxwell equations

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Surface-Response Formalism for light–matter interactions in Mesoscopic Plasmonics

Surface-Response Formalism for Light–Matter Interactions in...

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IEEE International Conference on Computational Electromagnetics (ICCEM)

作者： C. Tserkezis POLIMA-Center for Polariton-driven Light-Matter Interactions University of Southern Denmark Odense M Denmark

ISBN: (数字)9798350383317

ISBN: (纸本)9798350383324

The surface-response formalism (SRF) embodied by the Feibelman $d$ parameters offers a promising route for bridging the gap between the classical and quantum worlds in plasmonics. Without radically affecting the description of the system (typically one or more few-nm scatterers) in terms of Maxwell's equations and the bulk permittivity, SRF introduces effects of atomistic/solid-state origin via modification of the boundary conditions at the surface of the scatterer, and the inclusion of quantum effects through surface polarisation and current densities. Here we discuss the influence of these corrections on both the far-field spectra of the scatterers and on their coupling to quantum emitters.

关键词： Couplings Atomic measurements Plasmons Computational electromagnetics Boundary conditions Permittivity Maxwell equations

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Tunable nonlinear excitonic optical response in biased bilayer graphene

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Physical Review B 2024年第8期110卷 085433页

作者： M. F. C. Martins Quintela N. M. R. Peres T. Garm Pedersen Department of Physics and (INL) Av. Mestre José Veiga 4715-330 Braga Portugal Department of Materials and Production POLIMA–Center for Polariton-driven Light-Matter Interactions

Biased bilayer graphene (BBG) is an important system for studies of excitonic effects in graphene-based systems, with its easily tunable band gap. This band gap is governed by an external gate voltage, allowing one to tune the optical response of the system. In this paper, we study the excitonic linear and nonlinear optical responses of Bernal-stacked BBG as a function of the gate voltage, both for in-plane (IP) and out-of-plane (OOP) directions. Based on a semianalytical model of the electronic structure of BBG describing the influence of gate voltage on excitonic binding energies, we focus our discussion on both the IP and OOP excitonic responses. Both linear and second harmonic generation nonlinear responses are shown to be very sensitive to the gate voltage, as both the interband momentum matrix elements and the band gap of the system will vary greatly with bias potential.

关键词： Electrical conductivity Excitons Optical conductivity Optoelectronics Bilayer graphene

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Fourier analysis of near-field patterns generated by propagating polaritons

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Physical Review Applied 2024年第1期22卷 014076-014076页

作者： Minsoo Jang Sergey G. Menabde Fatemeh Kiani Jacob T. Heiden Vladimir A. Zenin N. Asger Mortensen Giulia Tagliabue Min Seok Jang School of Electrical Engineering Laboratory of Nanoscience for Energy Technologies (LNET) School of Engineering (STI) Center for Nano Optics POLIMA – Center for Polariton-driven Light-Matter Interactions Danish Institute for Advanced Study

Scattering-type scanning near-field optical microscope (s-SNOM) has become an essential tool to study polaritons—quasiparticles of light coupled to collective charge oscillations—via direct probing of their near field with a spatial resolution far beyond the diffraction limit. However, extraction of the polariton’s complex propagation constant from the near-field images requires subtle considerations that have not received the necessary attention so far. In this study, we discuss important yet overlooked aspects of the near-field analysis. First, we experimentally demonstrate that the sample orientation inside the s-SNOM may significantly affect the near-field interference pattern of mid-infrared polaritons, leading to an error in momentum measurement up to 7.7%, even for the modes with an effective index of 12.5. Second, we establish a methodology to correctly extract the polariton damping rate from the interference fringes depending on their origin—i.e., the s-SNOM nanotip or the material edge. Overall, our work provides a unified framework for the accurate extraction of the polariton momentum and damping from the near-field interference fringes.

关键词： Classical optics Nanophotonics Phonon polariton Surface & interfacial phenomena Nanotechnology Surfaces Scanning near-field optical microscopy

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Moiré excitons in biased twisted bilayer graphene under pressure

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Physical Review B 2024年第3期110卷 035405-035405页

作者： V. G. M. Duarte D. R. da Costa N. M. R. Peres L. K. Teles A. J. Chaves Departamento de Física Centro de Física das (INL) Avenida Mestre José Veiga 4715-330 Braga Portugal POLIMA—Center for Polariton-driven Light-Matter Interactions

Using the tight-binding model, we report a gap opening in the energy spectrum of a twisted bilayer graphene under the application of pressure, that can be further amplified by the presence of a perpendicular bias voltage. The valley edges are located along the K−Γ path of the superlattice Brillouin zone, with the band gap reaching values up to 200 meV in the single-particle picture. Employing the formalism of the semiconductor Bloch equations, we observe an enhancement of the band gap due to the electron-electron interaction, with a renormalization of the band gap of about 160 meV. From the solution of the corresponding Bethe-Salpeter equation, we show that this system supports highly anisotropic bright excitons whose electrons and holes are strongly hybridized between the adjacent layers.

关键词： Excitons Bilayer graphene Twisted heterostructures Bethe-Salpeter equation Random phase approximation Tight-binding model

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Quantum-informed plasmonics for strong coupling: the role of electron spill-out

arXiv

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arXiv 2023年

作者： Bundgaard, Ida Juliane Hansen, Christian Nicolaisen Stamatopoulou, P. Elli Tserkezis, Christos POLIMA Center for Polariton-driven Light-Matter Interactions University of Southern Denmark Campusvej 55 Odense MDK-5230 Denmark

The effect of nonlocality on the optical response of metals lies at the forefront of research in nanoscale physics and, in particular, quantum plasmonics. In alkali metals, nonlocality manifests predominantly as electron density spill-out at the metal boundary, and as surface-enabled Landau damping. For an accurate description of plasmonic modes, these effects need be taken into account in the theoretical modelling of the material. The resulting modal frequency shifts and broadening become particularly relevant when dealing with the strong interaction between plasmons and excitons, where hybrid modes emerge and the way they are affected can reflect modifications of the coupling strength. Both nonlocal phenomena can be incorporated in the classical local theory by applying a surface-response formalism embodied by the Feibelman parameters. Here, we implement surface-response corrections in Mie theory to study the optical response of spherical plasmonic–excitonic composites in core–shell configurations. We investigate sodium, a jellium metal dominated by spill-out, for which it has been anticipated that nonlocal corrections should lead to an observable change in the coupling strength, appearing as a modification of the width of the mode splitting. We show that, contrary to expectations, the influence of nonlocality on the anticrossing is minimal, thus validating the accuracy of the local response approximation in strong-coupling photonics. © 2023, CC BY.

关键词： Hazardous materials spills

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Mechanical Su-Schrieffer-Heeger quasicrystal: Topology, localization, and mobility edge

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Physical Review B 2024年第19期109卷 195427-195427页

作者： D. A. Miranda T. V. C. Antão N. M. R Peres Centro de Física (CF-UM-UP) and Departamento de Física Department of Applied Physics (INL) Avenida Mestre José Veiga 4715-330 Braga Portugal POLIMA–Center for Polariton-driven Light-Matter Interactions

In this paper we discuss the topological transition between trivial and nontrivial phases of a quasiperiodic (Aubry-André like) mechanical Su-Schrieffer-Heeger model. We find that there exists a nontrivial boundary separating the two topological phases, and an analytical expression for this boundary is found. We discuss the localization of the vibrational modes using the calculation of the inverse participation ratio and access the localization nature of the states of the system. We find three different regimes: extended, localized, and critical, depending on the intensity of the Aubry-André spring. We further study the energy-dependent mobility edge (ME) separating localized from extended eigenstates and find its analytical expression for both commensurate and incommensurate modulation wavelengths, thus enlarging the library of models possessing analytical expressions for the ME. Our results extend previous results for the theory of fermionic topological insulators and localization theory in quantum matter to the classical realm.

关键词： Localization Topological materials Hybrid model Su-Schrieffer-Heeger model Topology

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A Dedicated Modelling Scheme for Nonclassical Optical Response from the Nanosphere-on-Mirror Structure

arXiv

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arXiv 2023年

作者： Yan, Xiaotian Tserkezis, Christos Mortensen, N. Asger Vandenbosch, Guy A.E. Zheng, Xuezhi KU Leuven LeuvenB-3001 Belgium POLIMA Center for Polariton-driven Light-Matter Interactions University of Southern Denmark Odense5230 Denmark

Within the framework of the T-matrix method, we present a modeling tool that predicts the optical response from the Nanosphere-on-Mirror (NSoM) construct. The nonclassical effects in metals are accounted for by the nonlocal hydrodynamic Drude model (NLHDM) or the surface response model (SRM). Two essential elements in the T-matrix method, i.e., the T-matrix of the sphere and the R matrix accounting for the effects of the mirror, have been fully upgraded to include longitudinal waves for the NLHDM and the augmented interface conditions for the SRM. The proposed tool is quantitatively validated both in the near and the far field by an in-house developed BEM solver for the NLHDM where the gap between the sphere and the mirror is as small as 1 nm. Two physical checks are performed, where the results from the classical local response model are compared with the ones from the NLHDM and the SRM. The observed shifts in resonances and reduced field enhancements in the gap region agree well with previous physical findings. The proposed tool may not only serve as a reference tool for other numerical methods, but also provides an ideal platform for investigating nonclassical optical processes in the NSoM, hence paving a semi-analytical way to understand the extreme optics at very small scales. © 2023, CC BY.

关键词： Mirrors

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Coexistence of one-dimensional and two-dimensional topology and genesis of Dirac cones in the chiral Aubry-André model

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Physical Review B 2024年第19期109卷 195436-195436页

作者： T. V. C. Antão D. A. Miranda N. M. R. Peres Department of Applied Physics Centro de Física das Universidade do Minho e do Porto (CFUMUP) e Departamento de Física (INL) Av Mestre José Veiga 4715-330 Braga Portugal POLIMA - Center for Polariton-driven Light-Matter Interactions

We construct a one-dimensional (1D) topological SSH-like model with chiral symmetry and a superimposed hopping modulation, which we call the chiral Aubry-André model. We show that its topological properties can be described in terms of a pair (C,W) of a two-dimensional (2D) Chern number C, stemming from a superspace description of the model, and a 1D winding number W, originating in its chiral symmetric nature. Thus, we showcase the explicit coexistence of 1D and 2D topology in a model composed of a single 1D chain. We detail the superspace description by showcasing how our model can be mapped to a Harper-Hofstadter model, familiar from the description of the integer quantum Hall effect, and analyze the vanishing field limit analytically. An extension of the method used for vanishing fields is provided in order to handle any finite fields, corresponding to hopping modulations both commensurate and incommensurate with the lattice. In addition, this formalism allows us to obtain certain features of the 2D superspace model, such as its number of massless Dirac nodes, purely in terms of topological quantities, computed without the need to go into momentum space.

关键词： Chern insulators Edge states Integer quantum Hall effect Landau levels Phononic crystals Topological insulators Waveguide arrays 1-dimensional systems 2-dimensional systems Quasicrystals Topological materials Su-Schrieffer-Heeger model Topological tools

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Optical Singularities in Photonic Microstructures with Rosette Symmetries:A Unified Theoretical Scheme

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Engineering 2025年第2期45卷 59-69页

作者： Jie Yang Jiafu Wang Xinmin Fu Yueting Pan Tie Jun Cui Xuezhi Zheng Shaanxi Key Laboratory of Artificially Structured Functional Materials and Devices Xi’an 710051China Suzhou Laboratory Suzhou 215123China WaveCoRE Research Group KU LeuvenLeuven B-3001Belgium Faculty of Electronic and Information Engineering Xi’an Jiaotong UniversityXi’an 710049China Center for Advanced Quantum Studies Department of PhysicsBeijing Normal UniversityBeijing 100875China State Key Laboratory of Millimeter Wave Southeast UniversityNanjing 210096China Center for Polariton-Driven Light-Matter Interactions University of Southern DenmarkOdense 5230Denmark

Optical singularities are topological defects of electromagnetic fields;they include phase singularity in scalar fields,polarization singularity in vector fields,and three-dimensional(3D)singularities such as optical *** exploitation of photonic microstructures to generate and manipulate optical singularities has attracted wide research interest in recent years,with many photonic microstructures having been devised to this *** these designs,scattered phenomenological theories have been proposed to expound the working mechanisms behind individual *** this work,instead of focusing on a specific type of microstructure,we concentrate on the most common geometric features of these microstructures—namely,symmetries—and revisit the process of generating optical singularities in microstructures from a symmetry *** systematically employing the projection operator technique in group theory,we develop a widely applicable theoretical scheme to explore optical singularities in microstructures with rosette(i.e.,rotational and reflection)*** scheme agrees well with previously reported works and further reveals that the eigenmodes of a symmetric microstructure can support multiplexed phase singularities in different components,such as out-of-plane,radial,azimuthal,and left-and right-handed circular *** on these phase singularities,more complicated optical singularities may be synthesized,including C points,V points,L lines,Néel-and bubble-type optical skyrmions,and optical lattices,to name a *** demonstrate that the topological invariants associated with optical singularities are protected by the symmetries of the ***,based on symmetry arguments,we formulate a so-called symmetry matching condition to clarify the excitation of a specific type of optical *** work establishes a unified theoretical framework to explore optical singularities in photonic microstructures with symmetries,sheddin

关键词： Optical singularity Optical vortex Photonic microstructures Symmetries Group representation theory

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