Low-Symmetry Nanophotonics

TL;DR

This paper explores how breaking local symmetries in nanostructures enables novel control of light-matter interactions, advancing nanophotonics for diverse optical technologies.

Contribution

It provides a unified overview of symmetry violations in nanophotonics, highlighting their potential for tailoring optical functionalities at the nanoscale.

Findings

Symmetry breaking enables nonreciprocal light propagation.

Moiré photonics offers new ways to manipulate light.

In-plane inversion symmetry affects valleytronics applications.

Abstract

Photonics and optoelectronics are at the foundations of widespread technologies, from high-speed Internet to systems for artificial intelligence, automotive LiDAR, and optical quantum computing. Light enables ultrafast speeds and low energy for all-optical information processing and transport, especially when confined at the nanoscale level, at which the interactions of light with matter unveil new phenomena, and the role of local symmetries becomes crucial. In this Perspective, we discuss how symmetry violations provide unique opportunities for nanophotonics, tailoring wave interactions in nanostructures for a wide range of functionalities. We discuss geometrical broken symmetries for localized surface polaritons, the physics of moir\'e photonics, in-plane inversion symmetry breaking for valleytronics and nonradiative state control, time-reversal symmetry breaking for optical nonreciprocity, and parity-time symmetry breaking. Overall, our Perspective aims at presenting under a unified umbrella the role of symmetry breaking in controlling nanoscale light, and its widespread applications for optical technology.