Nonclassical optical response of particle plasmons with quantum informed local optics

TL;DR

This paper introduces a quantum-informed local analogue model (QILAM) that simplifies the analysis of nonclassical optical responses in plasmonic structures, making it compatible with efficient computational methods and connecting key semiclassical theories.

Contribution

The paper presents QILAM, a novel local dielectric model that maps nonclassical effects onto a local framework, compatible with boundary element methods and bridging GNOR and Feibelman theories.

Findings

QILAM effectively models nonlocal optical responses.

It simplifies computations by avoiding wavevector-dependent permittivity.

The framework links semiclassical theories for better understanding.

Abstract

As the dimensions of plasmonic structures or the field confinement length approach the mean free path of electrons, mesoscopic optical response effects, including nonlocality, electron density spill-in or spill-out, and Landau damping, are expected to become observable. In this work, we present a quantum-informed local analogue model (QILAM) that maps these nonclassical optical responses onto a local dielectric film. The primary advantage of this model lies in its compatibility with the highly efficient boundary element method (BEM), which includes retardation effects and eliminates the need to incorporate wavevector-dependent permittivity. Furthermore, our approach offers a unified framework that connects two important semiclassical theories: the generalized nonlocal optical response (GNOR) theory and the Feibelman d-parameters formalism. We envision that QILAM could evolve into a multiscale electrodynamic tool for exploring nonclassical optical responses in diverse plasmonic structures in future. This could be achieved by directly translating mesoscopic effects into observable phenomena, such as resonance energy shifts and linewidth broadening in the scattering spectrum.