Low-dimensional optical chirality in complex potentials

TL;DR

This paper introduces a novel approach to optical chirality using low-dimensional eigensystems in complex materials, enabling nonmagnetic chiral light interactions and predicting unique phenomena like optical spin black holes.

Contribution

It presents a new method for achieving optical chirality through low-dimensional polarization states, differing from traditional electric-magnetic mixing approaches.

Findings

Prediction of optical spin black holes.

Experimental confirmation of singular chiral interactions.

Demonstration of nonmagnetic chiral light interactions.

Abstract

Chirality is a universal feature in nature, as observed in fermion interactions and DNA helicity. Much attention has been given to chiral interactions of light, not only regarding its physical interpretation but also focusing on intriguing phenomena in excitation, absorption, refraction, and topological phase. Although recent progress in metamaterials has spurred artificial engineering of chirality, most approaches are founded on the same principle of the mixing of electric and magnetic responses. Here we propose nonmagnetic chiral interactions of light based on low-dimensional eigensystems. Exploiting the mixing of amplifying and decaying electric modes in a complex material, the low-dimensionality in polarization space having a chiral eigenstate is realized, in contrast to 2-dimensional eigensystems in previous approaches. The existence of optical spin black hole from low-dimensional chirality is predicted, and singular interactions between chiral waves are confirmed experimentally in parity-time-symmetric metamaterials.