Topological Photonics on a Small Scale

TL;DR

This paper reviews recent advances in nanoscale topological photonics, highlighting experimental demonstrations of small-scale topological states, novel platforms for topologically protected cavities, and future research directions.

Contribution

It provides a comprehensive overview of small-scale topological photonics, including experimental realizations and new platform proposals for subwavelength optical devices.

Findings

Demonstration of topological states in nanoparticle arrays

Development of higher-order topological photonic cavities

Progress in topological polaritonic structures

Abstract

The study of topological phases of light suggests novel opportunities for creating robust optical structures and on-chip photonic devices which are immune against scattering losses and structural disorder. However, many recent demonstrations of topological effects in optics employ structures with relatively large scales. Here we discuss the physics and realisation of topological photonics on small scales, with the dimensions often smaller or comparable with the wavelength of light. We highlight the recent experimental demonstrations of small-scale topological states based on arrays of resonant nanoparticles and discuss a novel photonic platform employing higher-order topological effects for creating subwavelength highly efficient topologically protected optical cavities. We pay a special attention to the recent progress on topological polaritonic structures and summarize with our vision on the future directions of nanoscale topological photonics and its impact on other fields.