Optical anapoles in nanophotonics and meta-optics

TL;DR

This paper reviews the concept of optical anapoles in nanophotonics, focusing on their physical principles, experimental observations, and applications in nanoantennas, metasurfaces, and nonlinear optics, highlighting their role in low-radiation states.

Contribution

It provides a comprehensive overview of the physics, experimental evidence, and emerging applications of optical anapoles in nanophotonics and meta-optics.

Findings

Experimental observation of optical anapoles in nanostructures

Demonstration of anapole states in nonlinear optics

Potential applications in low-loss nanoantennas and metasurfaces

Abstract

Interference of electromagnetic modes supported by subwavelength photonic structures is one of the key concepts that underpins the subwavelength control of light in meta-optics. It drives the whole realm of all-dielectric Mie-resonant nanophotonics with many applications for low-loss nanoscale optical antennas, metasurfaces, and metadevices. Specifically, interference of the electric and toroidal dipole moments results in a very peculiar, low-radiating optical state associated with the concept of optical anapole. Here, we uncover the physics of multimode interferences and multipolar interplay in nanostructures with an intriguing example of the optical anapole. We review the recently emerged field of anapole electrodynamics explicating its relevance to multipolar nanophotonics, including direct experimental observations, manifestations in nonlinear optics, and rapidly expanding applications in nanoantennas, active photonics, and metamaterials.