Chiral Quantum Optics

TL;DR

Chiral quantum optics explores how light-matter interactions depend on direction and polarization in nanostructures, enabling advanced quantum devices and networks with non-reciprocal and deterministic functionalities.

Contribution

This paper reviews the emerging field of chiral quantum optics, highlighting new mechanisms and applications for directional light-matter interactions in nanostructures.

Findings

Enables non-reciprocal single-photon devices

Facilitates deterministic spin-photon interfaces

Opens pathways for complex quantum networks

Abstract

At the most fundamental level, the interaction between light and matter is manifested by the emission and absorption of single photons by single quantum emitters. Controlling light--matter interaction is the basis for diverse applications ranging from light technology to quantum--information processing. Many of these applications are nowadays based on photonic nanostructures strongly benefitting from their scalability and integrability. The confinement of light in such nanostructures imposes an inherent link between the local polarization and propagation direction of light. This leads to {\em chiral light--matter interaction}, i.e., the emission and absorption of photons depend on the propagation direction and local polarization of light as well as the polarization of the emitter transition. The burgeoning research field of {\em chiral quantum optics} offers fundamentally new functionalities and applications both for single emitters and ensembles thereof. For instance, a chiral light--matter interface enables the realization of integrated non--reciprocal single--photon devices and deterministic spin--photon interfaces. Moreover, engineering directional photonic reservoirs opens new avenues for constructing complex quantum circuits and networks, which may be applied to simulate a new class of quantum many--body systems.