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Comparison of dynamic corrections to the quasistatic polarizability and optical properties of small spheroidal particles

journal contribution
posted on 2024-03-14, 18:22 authored by MRA Majić, Baptiste AuguiéBaptiste Auguié, Eric Le RuEric Le Ru
The optical properties of small spheroidal metallic nanoparticles can be simply studied within the quasistatic/electrostatic approximation, but this is limited to particles much smaller than the wavelength. A number of approaches have been proposed to extend the range of validity of this simple approximation to a range of sizes more relevant to applications in plasmonics, where resonances play a key role. The most common approach, called the modified long-wavelength approximation, is based on physical considerations of the dynamic depolarization field inside the spheroid, but alternative empirical expressions have also been proposed, presenting better accuracy. Recently, an exact Taylor expansion of the full electromagnetic solution has been derived [Majic et al., Phys. Rev. A 99, 013853 (2019)], which should arguably provide the best approximation for a given order. We here compare the merits of these approximations to predict orientation-averaged extinction/scattering/absorption spectra of metallic spheroidal nanoparticles. The Taylor expansion is shown to provide more accurate predictions over a wider range of parameters (aspect ratio and prolate/oblate shape). It also allows us to consider quadrupole and octupole resonances. This simple approximation can therefore be used for small and intermediate-size nanoparticles in situations where computing the full electromagnetic solution is not practical.

History

Preferred citation

Majić, M. R. A., Auguié, B. & Le Ru, E. C. (2022). Comparison of dynamic corrections to the quasistatic polarizability and optical properties of small spheroidal particles. Journal of Chemical Physics, 156(10), 104110-. https://doi.org/10.1063/5.0085687

Journal title

Journal of Chemical Physics

Volume

156

Issue

10

Publication date

2022-03-14

Pagination

104110

Publisher

AIP Publishing

Publication status

Published

Online publication date

2022-03-14

ISSN

0021-9606

eISSN

1089-7690

Article number

ARTN 104110

Language

en

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