Generalized method of images and reflective color generation from ultra-thin multipole resonators

TL;DR

This paper extends the method of images to multipole analysis for dielectric nanoparticles on conductive substrates, enabling new insights and applications such as high-resolution surface color generation.

Contribution

It generalizes the method of images for multipole analysis in inhomogeneous environments and demonstrates a novel high-resolution color generation mechanism using ultra-thin dielectric resonators.

Findings

Generalized method provides physical insights into multipole excitation

Experimental demonstration of high-resolution surface color

New design possibilities for metasurfaces and dielectric resonators

Abstract

The multipole expansion has found limited applicability for optical dielectric resonators in inhomogeneous environment, such as on the surface of substrates. Here, we generalize the method of images to multipole analysis for light scattering by dielectric nanoparticles on conductive substrates. We present examples illustrating the physical insight provided by our method, including selection rules governing the excitation of the multipoles. We propose and experimentally demonstrate a new mechanism to generate high resolution surface color. The dielectric resonators employed are very thin (less than 50 nm), i.e. similar in thickness to the plasmonic resonators that are currently being investigated for structural color. The generalized method of images opens up new prospects for design and analysis of metasurfaces and optical dielectric resonators.