Polarization-controlled selective excitation of Mie resonances of dielectric nanoparticle on a coated substrate

TL;DR

This paper demonstrates how polarization and layer thickness can control the excitation of electric and magnetic Mie resonances in silicon nanoparticles on a substrate, enabling switchable optical responses and scattering directions.

Contribution

It introduces a method to control nanoparticle resonances and scattering via polarization and substrate thickness, advancing tunable nanophotonic device design.

Findings

Polarization controls multipole excitation at specific angles.

Layer thickness influences electric and magnetic resonance contributions.

Scattering direction can be switched by polarization changes.

Abstract

High-index spherical nanoparticles with low material losses support sharp high-Q electric and magnetic resonances and exhibit a number of interesting optical phenomena. Developments in fabrication techniques have enabled the further study of their properties and the investigation of related optical effects. After deposition on a substrate, the optical properties of a particle change dramatically due to mutual interaction. Here, we consider a silicon spherical nanoparticle on a dielectric one-layered substrate. At the normal incidence of light, the layer thickness controls the contribution of the nanoparticle's electric and magnetic multipoles to the subsequent optical response. We show that changing the polarization of incident light at a specific excitation angle and layer thickness leads to switching between the multipoles. We further observe a related polarization-driven control over the direction of the scattered radiation.