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Electromagnetic theory, scattering and diffraction
14:00: Scattering by a dielectric cylinder with arbitrary cross section using Pseudo-spectral Modal Method
Tsirinantenaina A. Rafalimanana (1), Gerard Granet (2), Karyl Danielson Raniriharinosy (1)
(1)Université de Fianarantsoa (Madagascar) , (2)Université Clermont Auvergne (France)
We present a new semi-analytical formulation for diffraction by structured cylinders. A pseudo-spectral modal method is used to solve the Maxwell equations written in curvilinear coordinates. The program is compared with the numerical results obtained with finite element method using Comsol Multiphysics.
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14:15 Invited talk: GSTC formulation for Maxwell's equations
Agnès Maurel (1), Nicolas Lebbe (1), Kim Pham (2)
(1)Université de Paris (France) , (2)Université Paris-Saclay (France)
We revisit the classical zero-thickness Generalized Sheet Transition Conditions (GSTCs) which are a key tool for efficiently designing metafilms able to control the flow of light in a desired way.
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14:35 Invited talk: Symmetry protected and accidental bound states in the continuum in photonic-crystal structures, studied by the resonant-state expansion
Sam Neale, Egor Muljarov
Cardiff University (United Kingdom)
We apply the resonant-state expansion (RSE), a novel rigorous theoretical method in electrodynamics, to planar photonic-crystal structures, to study their eigenmodes, and in particular bound states in the continuum (BICs). Using the high efficiency of the RSE, we investigate the mode evolution with changes to the geometrical and material parameters of the system. Increasing the amplitude of the periodic modulation of the permittivity, we demonstrate formation of symmetry protected and accidental BICs in photonic-crystal structures and study their properties.
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14:55: First-order perturbation theory for electromagnetic eigenmodes
Zoltan Sztranyovszky, Wolfgang Langbein, Egor A. Muljarov
Cardiff University (United Kingdom)
We present an accurate first order perturbation theory for the electromagnetic eigenmodes of a resonator, which is based on the spectral representation of the Green's dyadic. We show that when the resonator boundary is deformed, higher-order terms of the standard perturbation series can contribute to the eigenmode frequencies in first-order in the deformation depth. This is a consequence of the vectorial nature of the electromagnetic field and the infinite degeneracy of static modes of the resonator.
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15:10 Invited talk: Limits on Electromagnetic Scattering
Pengning Chao (1), Benjamin Strekha (1), Rodrick K. Defo (1), Sean Molesky (2), Alejandro W. Rodriguez (1)
(1)Princeton University (USA) , (2)Polytechnique Montreal (Canada)
While improvements in nanofabrication and computational methods have driven dramatic progress in expanding the range of achievable optical characteristics, they have also greatly increased design complexity. These developments have led to heightened relevance for the study of fundamental limits on optical response. Here, we review recent progress in our understanding of these limits with special focus on an emerging theoretical framework that combines computational optimization with conservation laws to yield physical limits capturing all relevant wave effects.
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