Quantum Key Distribution Using a Quantum Emitter in Hexagonal Boron Nitride

Abstract

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 ε‐security of 10−10 are generated. This study demonstrates the first proof of concept finite‐key BB84 QKD system realized with hBN defects.

Comparative Study of Quantum Emitter Fabrication in Wide Bandgap Materials Using Localized Electron Irradiation

“…Quantum emitters in solid-state crystals have garnered considerable attention, driven by the rapid advancement of quantum technology applications such as quantum computing, quantum communication, and quantum sensing. − The discovery of quantum emitters based on defects in wide bandgap materials has significantly advanced this field. − Quantum emitters have been used in a wide variety of applications, most prominently in magnetometry and imaging, , but also in quantum key distribution, , fundamental quantum physics tests, thermometry, pressure sensing, quantum computing, quantum memories, − and as nodes in a quantum network …”

“…1−5 The discovery of quantum emitters based on defects in wide bandgap materials has significantly advanced this field. 6−11 Quantum emitters have been used in a wide variety of applications, most prominently in magnetometry and imaging, 12,13 but also in quantum key distribution, 4,5 fundamental quantum physics tests, 14 thermometry, 15 pressure sensing, 16 quantum computing, 17 quantum memories, 18−20 and as nodes in a quantum network. 21 Probably the most-well studied solid-state quantum emitter is the nitrogen vacancy center in diamond 22 and related defects, such as the group-IV color centers.…”

First-principles theory of the nitrogen interstitial in hBN: a plausible model for the blue emitter

“…8,9 Due to its layered structure, hBN also offers versatile integration capabilities for photonic applications. 7,10…”

Combining experiments on luminescent centres in hexagonal boron nitride with the polaron model and ab initio methods towards the identification of their microscopic origin

“…Luminescent centres in hexagonal boron nitride (hBN) have gained an increased scientific interest due to the demonstration of single photon emission with a brightness comparable to semiconductor quantum dots. 1 These luminescent centres emit at photon energies around 2 eV and persist even at room temperature, 2 making hBN a promising material to realise future optoelectronic technologies such as quantum telecommunication 3,4 and quantum sensing. 5…”