Plasmon Polaritons in Disordered Nanoparticle Assemblies

Fuente: arXiv
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Main Authors: Paul, Tanay, Green, Allison M., Milliron, Delia J., Truskett, Thomas M.
Format: Preprint
Published: 2025
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author Paul, Tanay
Green, Allison M.
Milliron, Delia J.
Truskett, Thomas M.
author_facet Paul, Tanay
Green, Allison M.
Milliron, Delia J.
Truskett, Thomas M.
contents Multilayer assemblies of metal nanoparticles can act as photonic structures, where collective plasmon resonances hybridize with cavity modes to create plasmon-polariton states. For sufficiently strong coupling, plasmon polaritons qualitatively alter the optical properties of light-matter systems, with applications ranging from sensing to solar energy. However, results from experimental studies have raised questions about the role of nanoparticle structural disorder in plasmon-polariton formation and light-matter coupling in plasmonic assemblies. Understanding how disorder affects optical properties has practical implications since methods for assembling low-defect nanoparticle superlattices are slow and scale poorly. Modeling realistic disorder requires large system sizes, which is challenging using conventional electromagnetic simulations. We employ Brownian dynamics simulations to construct large-scale nanoparticle multilayers with controlled structural order. We investigate their optical response using a superposition T-matrix method with 2-D periodic boundary conditions. We find that while structural disorder broadens the polaritonic stop band and the near-field hot-spot distribution, the polariton dispersion and coupling strength remain unaltered. To understand effects of nanoparticle composition, we consider assemblies with model particles mimicking gold or tin-doped indium oxide (ITO) nanocrystals. Losses due to higher damping in ITO nanocrystals prevent their assemblies from achieving the deep strong coupling of gold nanoparticle multilayers, although the former still exhibit ultrastrong coupling. We demonstrate that while computationally efficient mutual polarization method calculations employing the quasistatic approximation modestly overestimate the strength of the collective plasmon, they reproduce the polariton dispersion relations determined by electrodynamic simulations.
format Preprint
id arxiv_https___arxiv_org_abs_2506_18138
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Plasmon Polaritons in Disordered Nanoparticle Assemblies
Paul, Tanay
Green, Allison M.
Milliron, Delia J.
Truskett, Thomas M.
Optics
Disordered Systems and Neural Networks
Mesoscale and Nanoscale Physics
Materials Science
Multilayer assemblies of metal nanoparticles can act as photonic structures, where collective plasmon resonances hybridize with cavity modes to create plasmon-polariton states. For sufficiently strong coupling, plasmon polaritons qualitatively alter the optical properties of light-matter systems, with applications ranging from sensing to solar energy. However, results from experimental studies have raised questions about the role of nanoparticle structural disorder in plasmon-polariton formation and light-matter coupling in plasmonic assemblies. Understanding how disorder affects optical properties has practical implications since methods for assembling low-defect nanoparticle superlattices are slow and scale poorly. Modeling realistic disorder requires large system sizes, which is challenging using conventional electromagnetic simulations. We employ Brownian dynamics simulations to construct large-scale nanoparticle multilayers with controlled structural order. We investigate their optical response using a superposition T-matrix method with 2-D periodic boundary conditions. We find that while structural disorder broadens the polaritonic stop band and the near-field hot-spot distribution, the polariton dispersion and coupling strength remain unaltered. To understand effects of nanoparticle composition, we consider assemblies with model particles mimicking gold or tin-doped indium oxide (ITO) nanocrystals. Losses due to higher damping in ITO nanocrystals prevent their assemblies from achieving the deep strong coupling of gold nanoparticle multilayers, although the former still exhibit ultrastrong coupling. We demonstrate that while computationally efficient mutual polarization method calculations employing the quasistatic approximation modestly overestimate the strength of the collective plasmon, they reproduce the polariton dispersion relations determined by electrodynamic simulations.
title Plasmon Polaritons in Disordered Nanoparticle Assemblies
topic Optics
Disordered Systems and Neural Networks
Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2506.18138