A photonic interface of chiral cavity quantum electrodynamics

TL;DR

This paper proposes a novel photonic structure combining photonic crystals and metallic nanoparticles to achieve strong, unidirectional light-matter interactions, enabling potential nonreciprocal quantum devices with enhanced emission rates.

Contribution

It introduces a new coupled photonic crystal and nanoparticle system that significantly enhances chiral photon-emitter coupling and unidirectional emission, advancing nonreciprocal quantum photonic applications.

Findings

Emission rate increased by an order of magnitude with nanoparticle

Linewidth of Rabi splitting reduced to one-tenth

Approximately 95% of photons propagate unidirectionally

Abstract

Cavity quantum electrodynamics studies light-matter interactions at single quanta level. Chiral photon-emitter coupling in photonic structures is characterized as unidirectional propagation locked by the local polarization of light. However, to realize the strong interaction of photon-emitter with direction-locked propagation, which will bring novel applications in nonreciprocal quantum devices, has not been reported yet. Here, we propose the coupled photonic crystal and metallic nanoparticle structure, where through strong local field with high helicity, the rate of circularly polarized photons emitting into photonic crystal waveguide is one order larger than that without the nanoparticle and the linewidth of Rabi splitting spectra is about one-tenth of that with only the nanoparticle, both with $\sim$ 95$\%$ photons propagating unidirectionally, which can be utilized in directional quantum light sources.