General Systropy in Spherical Scatterers

Rimpiläinen, Tommi; Pitkonen, Mikko; Wallén, Henrik; Kettunen, Henrik; Sihvola, Ari

doi:10.1109/tap.2013.2290540

Cited by 4 publications

(2 citation statements)

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“…This seminal work has been followed by research on the exotic scattering response of these structures [10][11][12][13][14]. In subsequent work, the spherical geometry has been generalized into a spheroidal one [15,16] and the uniaxial material has been generalized into biaxial [17,18]. Another flavor of radial anisotropy is the cylindrical anisotropy.…”

Section: Introductionmentioning

confidence: 99%

Implementing radial anisotropy with self-similar structures

2020

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Radial anisotropy in small objects has been linked to exotic optical properties. It can be implemented with a spherical inclusion that manifests self-similarity. We show that, when a self-similar, onion-like structure with alternating layers is homogenized by using an effective material approximation, the homogenized material becomes uniaxially anisotropic with the axis of anisotropy pointed radially outward from the center of the inclusion. This radial anisotropy becomes exact in the limit of a dense set of layers. The exact equivalence of the layered self-similar inclusion and the radially anisotropic inclusion manifests itself both in the effective permittivities of the two inclusions-when homogenized over the entire volumes-and in the internal potentials. Because the layered sphere and the radially anisotropic sphere are analogous, it is possible to study some of the interesting scattering features of radially anisotropic spheres in a realistic configuration. In particular, we show that the outcome of homogenizing the self-similar inclusion, and consequently the electric response, depends on what the core material at the center of the inclusion is and that a continuous transition between the two homogenization models is possible. The findings suggest intriguing applications in nanophotonics.

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Section: Introductionmentioning

confidence: 99%

Implementing radial anisotropy with self-similar structures

2020

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“…1). While the homogeneous elliptic cylinder has been studied for both dynamic and static fields 5 and while the concept of radial anisotropy has been considered for circular cylinders 8,9 and spheres 10-15 before, even in a generalized sense, 16,17 the present study examines electrostatic scattering with a combination of material and geometric properties unprecedented, as far as the authors know, in the electromagnetic literature.…”

Section: Introductionmentioning

confidence: 99%

Polarizability of radially anisotropic elliptic inclusion

Rimpiläinen

Wallén

Sihvola

2016

Journal of Applied Physics

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This article discusses a two-dimensional electrostatic scattering problem where an elliptic inclusion is suspended in a homogeneous background and impinged by an electric field which is uniform and static. The novelty of the discussion stems from the inclusion's material parameters. The material of the inclusion is assumed to be axially anisotropic, so that the axis of anisotropy aligns itself with the radial unit vector of the elliptic coordinate system. Similar varieties of anisotropy have been formerly referred to as radial anisotropy, and the same term is employed herein. The radially anisotropic elliptic inclusions are studied with an analytic method. The validation is likewise analytic. The validation method compares the new results with the results for radially anisotropic circles and homogeneous two-dimensional needles. The elliptic inclusion is found to facilitate both cloaking and field concentration. V C 2016 AIP Publishing LLC. [http://dx.

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