Quantum Key Distribution Using a Quantum Emitter in Hexagonal Boron Nitride

Quantum key distribution (QKD) is considered the most immediate application to be widely implemented among a variety of potential quantum technologies. QKD enables sharing secret keys between distant users by using photons as information carriers. An ongoing endeavor is to implement these protocols in practice in a robust, and compact manner so as to be efficiently deployable in a range of real-world scenarios. Single photon sources (SPS) in solid-state materials are prime candidates in this respect. This article demonstrates a room temperature, discrete-variable quantum key distribution system using a bright single photon source in hexagonal-boron nitride, operating in free-space. Employing an easily interchangeable photon source system, keys with one million bits length, and a secret key of approximately 70000 bits, at a quantum bit error rate of 6%, with & epsilon;-security of 10(-10) are generated. This study demonstrates the first proof of concept finite-key BB84 QKD system realized with hBN defects.