Topological cavity based on slow light topological edge mode for broadband Purcell enhancement

TL;DR

This paper introduces a topological cavity utilizing slow light edge modes in valley photonic crystals, achieving broadband Purcell enhancement and high-quality cavity modes for improved quantum light sources.

Contribution

It presents the first experimental demonstration of a topological cavity with slow light edge modes for broadband Purcell enhancement in valley photonic crystals.

Findings

Large group indices over 100 achieved

Enhanced Purcell factor demonstrated

Broadband cavity modes with high quality factor

Abstract

Slow light in topological valley photonic crystal structures offers new possibilities to enhance light-matter interaction. We report a topological cavity based on slow light topological edge mode for broadband Purcell enhancement. The topological edge modes with large group indices over 100 can be realized with a bearded interface between two topologically distinct valley photonic crystals, featuring the greatly enhanced Purcell factor because of the increased local density of states. In the slow light regime, the topological cavity supports much more cavity modes with higher quality factor than that in the fast light regime, which is both demonstrated theoretically and experimentally. We demonstrate the cavity enables the broadband Purcell enhancement together with substantial Purcell factor, benefiting from dense cavity modes with high quality factor in a wide spectral range. It has great benefit to the realization of high-efficiency quantum-dot-based single-photon sources and entangled-photon sources with less restriction on spectral match. Such topological cavity could serve as a significant building block toward the development of photonic integrated circuits with embedded quantum emitters.