Analytical models for coated plasmonic particles: effects of shape and size-corrected dielectric function

Fuente: arXiv
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Main Authors: Khlebtsov, Nikolai G., Zarkov, Sergey V.
Format: Preprint
Published: 2025
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author Khlebtsov, Nikolai G.
Zarkov, Sergey V.
author_facet Khlebtsov, Nikolai G.
Zarkov, Sergey V.
contents Recently, modal expansion methods (MEMs) were developed to accurately predict the extinction and scattering spectra of bare and coated plasmonic particles. However, it remains uncertain whether the accuracy of analytical models is preserved when incorporating size-corrected dielectric functions. We compare numerical (COMSOL) and analytical extinction and scattering spectra for various particle shapes - rods, disks, prisms, bicones, and bipyramids - using both bulk and size-corrected dielectric functions. Size correction primarily causes broadening and a reduction in the plasmonic peaks. Still, the accuracy of analytical models is maintained for all shapes except sharp bicones, where MEM fails for both bulk and size-corrected dielectric functions. This failure arises from the strong localization of the plasmonic field near the sharp bicone tips. However, for realistic bicone models with nanometer-scale tip curvature, MEM performs well.
format Preprint
id arxiv_https___arxiv_org_abs_2508_11248
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Analytical models for coated plasmonic particles: effects of shape and size-corrected dielectric function
Khlebtsov, Nikolai G.
Zarkov, Sergey V.
Optics
Mesoscale and Nanoscale Physics
Chemical Physics
Recently, modal expansion methods (MEMs) were developed to accurately predict the extinction and scattering spectra of bare and coated plasmonic particles. However, it remains uncertain whether the accuracy of analytical models is preserved when incorporating size-corrected dielectric functions. We compare numerical (COMSOL) and analytical extinction and scattering spectra for various particle shapes - rods, disks, prisms, bicones, and bipyramids - using both bulk and size-corrected dielectric functions. Size correction primarily causes broadening and a reduction in the plasmonic peaks. Still, the accuracy of analytical models is maintained for all shapes except sharp bicones, where MEM fails for both bulk and size-corrected dielectric functions. This failure arises from the strong localization of the plasmonic field near the sharp bicone tips. However, for realistic bicone models with nanometer-scale tip curvature, MEM performs well.
title Analytical models for coated plasmonic particles: effects of shape and size-corrected dielectric function
topic Optics
Mesoscale and Nanoscale Physics
Chemical Physics
url https://arxiv.org/abs/2508.11248