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Q: Fachverband Quantenoptik und Photonik
Q 59: QuanTour V – Protocols
Q 59.1: Invited Talk
Thursday, March 5, 2026, 14:30–15:00, P 7
High-Speed Quantum Key Distribution using Single Photons from Defects in Hexagonal Boron Nitride — Furkan Ağlarci1, Ömer S. Tapşin1, Çağlar Samaner1, Serkan Paçal1, and •Serkan Ateş1,2 — 1Department of Physics, Izmir Institute of Technology, Izmir, Türkiye — 2Faculty of Engineering and Natural Sciences, Sabanci University, Tuzla, Istanbul, Türkiye
We present an experimental demonstration of free-space Quantum Key Distribution (QKD) utilizing single photons generated from optically active defects in hexagonal boron nitride (hBN) operating at room temperature (RT). In our implementation of the B92 protocol, we successfully integrated the hBN single-photon source (SPS) with a resonant electro-optic modulator, enabling dynamic polarization encoding at a 40 MHz clock rate. This high-speed operation yielded a sifted key rate of 17.5 kbps and a secure key rate (SKR) of 7 kbps with a Quantum Bit Error Rate of 6.49%, representing one of the highest reported SKRs for a RT-SPS with active polarization modulation. We benchmark this performance against other quantum emitters and analyze the potential of hBN defects in a hypothetically secured BB84 framework. We show that with achievable improvements, such as microcavity coupling, the source has the potential to reach an SKR in the Mbps range. This work highlights the versatility and maturity of hBN defects as bright, RT-SPS, paving the way for practical, high-speed, and miniaturized quantum communication systems, including future space-based QKD missions.
Keywords: hBN; single photon source; quantum key distribution