Cavity-Quantum Electrodynamics with Moir\'e Flatband Photonic Crystals

TL;DR

This paper introduces a moiré photonic crystal cavity with flatband dispersion that significantly enhances and controls quantum emitter emission, demonstrating tunable quantum dot lifetimes and potential for quantum technologies.

Contribution

The study presents a novel multilayer moiré photonic crystal cavity design that achieves high Purcell factors with positional tolerance, enabling advanced quantum light sources and quantum network components.

Findings

Achieved a 40-fold tuning of quantum dot lifetime from 42 ps to 1692 ps.

Demonstrated strong Purcell enhancement and inhibition effects.

Validated coupling between moiré cavity and quantum dot through polarization control.

Abstract

Quantum emitters are a key component in photonic quantum technologies. Enhancing their single-photon emission by engineering the photonic environment using cavities can significantly improve the overall efficiency in quantum information processing. However, this enhancement is often constrained by the need for precise nanoscale control over the emitter's position within micro- or nano-cavities. Inspired by the fascinating physics of moir\'e patterns, we present an approach to strongly modify the spontaneous emission rate of a quantum emitter using a finely designed multilayer moir\'e photonic crystal with a robust isolated-flatband dispersion. Theoretical analysis reveals that, due to its nearly infinite photonic density of states, the moir\'e cavity can simultaneously achieve a high Purcell factor and exhibit large tolerance over the emitter's position. We experimentally demonstrate the coupling between this moir\'e cavity and a quantum dot through the cavity-determined polarization of the dot's emission. The radiative lifetime of the quantum dot can be tuned by a factor of 40, ranging from 42 ps to 1692 ps, which is attributed to strong Purcell enhancement and Purcell inhibition effects. Our findings pave the way for moir\'e flatband cavity-enhanced quantum light sources, quantum optical switches, and quantum nodes for quantum internet applications.