# Extraordinary subradiance with lossless excitation transfer in dipole-coupled nano-rings of quantum emitters

## TL;DR

This paper demonstrates how to enhance and control subradiant modes in coupled quantum emitter rings, enabling high-fidelity excitation transfer with potential applications in nano-scale quantum optics.

## Contribution

It introduces a method to tailor ring geometries and orientations to significantly boost coherent coupling and facilitate efficient excitation transfer between quantum emitter rings.

## Key findings

- Subradiant modes form a nano-scale high-Q optical resonator.
- Tailoring geometry increases ring-to-ring coupling by several orders of magnitude.
- High-fidelity transport of delocalized excitations between rings.

## Abstract

A ring of sub-wavelength spaced dipole-coupled quantum emitters possesses only few radiant but many extraordinarily subradiant collective modes. These exhibit a 3D-confined spatial radiation field pattern forming a nano-scale high-Q optical resonator. We show that tailoring the geometry, orientation and distance between two such rings allows for increasing the ratio of coherent ring-to-ring coupling versus free-space emission by several orders of magnitude. In particular we find that subradiant excitations, when delocalized over several ring sites, are effectively transported between the rings with a high fidelity.