Polarizability of Radially Inhomogeneous Subwavelength Spheres

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Polarizability of Radially Inhomogeneous Subwavelength Spheres. / Tzarouchis, Dimitrios C.; Sihvola, Ari.

In: Physical Review Applied, Vol. 10, No. 5, 06.11.2018.

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@article{15665bfc27d94a39aca9967fcb763385,
title = "Polarizability of Radially Inhomogeneous Subwavelength Spheres",
abstract = "In this work the polarizability of a subwavelength core-shell sphere is considered, where the shell exhibits a radially inhomogeneous permittivity profile. The mathematical treatment of the electrostatic polarizability is formulated in terms of the scattering potentials and the corresponding scattering amplitudes. As a result, a generalized expression of the polarizability is presented to be dependent of the radial inhomogeneity function. The extracted general model is applied for two particular cases, i.e., a power-law profile and a new class of permittivity profiles that exhibit exponential radial dependence. The proposed analysis quantifies in a simple manner the inhomogeneity effects, allowing the direct implementation of naturally or artificially occurring permittivity inhomogeneities for a wide range of applications within and beyond the metamaterial paradigm. Specifically, a special case of symmetric-antisymmetric resonant plasmonic degeneracy is identified and shown for the case of a core-shell sphere with a power-law permittivity profile. This degeneracy could be used for the experimental identification of inhomogeneity-induced effects or for applications where a strong coupling resonant regime is required. Furthermore, the described analysis opens avenues towards the phenomenological and first-principles modeling of the electrodynamic scattering effects for graded-index plasmonic particles at the nanoscale. Finally, such a description can be readily used either for the benchmarking of novel computational methods incorporating inhomogeneous materials or for inverse scattering purposes.",
author = "Tzarouchis, {Dimitrios C.} and Ari Sihvola",
year = "2018",
month = "11",
day = "6",
doi = "10.1103/PhysRevApplied.10.054012",
language = "English",
volume = "10",
journal = "Physical Review Applied",
issn = "2331-7019",
publisher = "American Physical Society",
number = "5",

}

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TY - JOUR

T1 - Polarizability of Radially Inhomogeneous Subwavelength Spheres

AU - Tzarouchis, Dimitrios C.

AU - Sihvola, Ari

PY - 2018/11/6

Y1 - 2018/11/6

N2 - In this work the polarizability of a subwavelength core-shell sphere is considered, where the shell exhibits a radially inhomogeneous permittivity profile. The mathematical treatment of the electrostatic polarizability is formulated in terms of the scattering potentials and the corresponding scattering amplitudes. As a result, a generalized expression of the polarizability is presented to be dependent of the radial inhomogeneity function. The extracted general model is applied for two particular cases, i.e., a power-law profile and a new class of permittivity profiles that exhibit exponential radial dependence. The proposed analysis quantifies in a simple manner the inhomogeneity effects, allowing the direct implementation of naturally or artificially occurring permittivity inhomogeneities for a wide range of applications within and beyond the metamaterial paradigm. Specifically, a special case of symmetric-antisymmetric resonant plasmonic degeneracy is identified and shown for the case of a core-shell sphere with a power-law permittivity profile. This degeneracy could be used for the experimental identification of inhomogeneity-induced effects or for applications where a strong coupling resonant regime is required. Furthermore, the described analysis opens avenues towards the phenomenological and first-principles modeling of the electrodynamic scattering effects for graded-index plasmonic particles at the nanoscale. Finally, such a description can be readily used either for the benchmarking of novel computational methods incorporating inhomogeneous materials or for inverse scattering purposes.

AB - In this work the polarizability of a subwavelength core-shell sphere is considered, where the shell exhibits a radially inhomogeneous permittivity profile. The mathematical treatment of the electrostatic polarizability is formulated in terms of the scattering potentials and the corresponding scattering amplitudes. As a result, a generalized expression of the polarizability is presented to be dependent of the radial inhomogeneity function. The extracted general model is applied for two particular cases, i.e., a power-law profile and a new class of permittivity profiles that exhibit exponential radial dependence. The proposed analysis quantifies in a simple manner the inhomogeneity effects, allowing the direct implementation of naturally or artificially occurring permittivity inhomogeneities for a wide range of applications within and beyond the metamaterial paradigm. Specifically, a special case of symmetric-antisymmetric resonant plasmonic degeneracy is identified and shown for the case of a core-shell sphere with a power-law permittivity profile. This degeneracy could be used for the experimental identification of inhomogeneity-induced effects or for applications where a strong coupling resonant regime is required. Furthermore, the described analysis opens avenues towards the phenomenological and first-principles modeling of the electrodynamic scattering effects for graded-index plasmonic particles at the nanoscale. Finally, such a description can be readily used either for the benchmarking of novel computational methods incorporating inhomogeneous materials or for inverse scattering purposes.

UR - http://www.scopus.com/inward/record.url?scp=85056321570&partnerID=8YFLogxK

U2 - 10.1103/PhysRevApplied.10.054012

DO - 10.1103/PhysRevApplied.10.054012

M3 - Article

VL - 10

JO - Physical Review Applied

JF - Physical Review Applied

SN - 2331-7019

IS - 5

ER -

ID: 29768210