# Scattering invisibility with free-space field enhancement of all-dielectric nanoparticles

## TL;DR

This paper demonstrates how all-dielectric nanoparticles can achieve simultaneous scattering invisibility and free-space field enhancement through multipolar interference, with potential applications in sensing and medical diagnosis.

## Contribution

It introduces a novel mechanism for scattering invisibility involving multipolar interferences and magnetoelectric interactions in dielectric nanowire quadrumers.

## Key findings

- Identified two types of scattering invisibility: trivial and nontrivial.
- Nontrivial invisibility involves strong multipolar excitations and field enhancement.
- Invisibility is polarization and direction selective.

## Abstract

Simultaneous scattering invisibility and free-space field enhancement have been achieved based on multipolar interferences among all-dielectric nanoparticles. The scattering properties of all-dielectric nanowire quadrumers are investigated and two sorts of scattering invisibilities have been identified: the trivial invisibility where the individual nanowires are not effectively excited; and the nontrivial invisibility with strong multipolar excitations within each nanowire, which results in free-space field enhancement outside the particles. It is revealed that such nontrivial invisibility originates from not only the simultaneous excitations of both electric and magnetic resonances, but also their significant magnetoelectric cross-interactions. We further show that the invisibility obtained is both polarization and direction selective, which can probably play a significant role in various applications including non-invasive detection, sensing, and non-disturbing medical diagnosis with high sensitivity and precision.