Exotic Cooperative Quantum Optics of Moire Exciton Superlattices

TL;DR

This paper explores how moire exciton superlattices can exhibit cooperative optical responses, including switchable superradiant and subradiant states, enabling potential applications in quantum optics such as photon storage and switching.

Contribution

It demonstrates that moire exciton superlattices can be engineered to exhibit controllable cooperative optical phenomena, a novel approach in quantum optics research.

Findings

Moire excitons form ordered superlattices with optical wavelength-scale lattice constants.

Collective exciton states can be switched between superradiant and subradiant regimes.

The system's transmittance can be toggled from opaque to transparent with minimal strain or twist adjustments.

Abstract

The unique properties of two-dimensional moire systems have been widely studied from many perspectives. However, relatively little work has explored how the real space structure of the moire systems can directly engender novel properties and functionalities. In this work, we exploit the feature that moire excitons naturally form an ordered superlattice with a lattice constant comparable to the wavelength of the resonant light, which enables intriguing cooperative optical responses. Particularly, we show that the collective moire exciton states can have either strongly enhanced (superradiant) or suppressed (subradiant) radiative decay rate, depending on their in-plane wavevector. These super- and subradiant states can be efficiently switched by a gate-induced electric field gradient. Moreover, the cooperative transmittance $T$ of the nanometer-thick moire system can be switched from $T \approx 0$ (opaque) to $T \approx 1$ (transparent) with less than $2~\%$ heterostrain or a $1^{\circ}$ adjustment in the twist angle $\theta$. These features are robust against non-radiative losses and inhomogeneity, making the moire system a highly versatile platform for cooperative quantum optics with potential applications in e.g., single photon storage and switching.