Atomically-thin Single-photon Sources for Quantum Communication

Abstract

To date, quantum communication widely relies on attenuated lasers for secret key generation. In future quantum networks fundamental limitations resulting from their probabilistic photon distribution must be overcome by using deterministic quantum light sources. Confined excitons in monolayers of transition metal dichalcogenides (TMDCs) constitute a novel type of emitter for quantum light generation. These atomically-thin solid-state sources show appealing prospects for large-scale and low-cost device integration, meeting the demands of quantum information technologies. Here, we pioneer the practical suitability of TMDC devices in quantum communication. We employ a WSe2 monolayer single-photon source to emulate the BB84 protocol in a quantum key distribution (QKD) setup and achieve raw key rates of up to 66.95 kHz and antibunching values down to 0.034 -a performance competitive with QKD experiments using semiconductor quantum dots or color centers in diamond. Our work opens the route towards wider applications of quantum information technologies using TMDC single-photon sources.

Free‐Space Quantum Key Distribution with Single Photons from Defects in Hexagonal Boron Nitride

“…Note: We are aware of a recent report on an emulation of QKD with single photon emission from a monolayer TMDC material at cryogenic temperature. [57]…”