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

Samaner, Çağlar; Paçal, Serkan; Mutlu, Görkem; Uyanık, Kıvanç; Ateş, Serkan

doi:10.1002/qute.202200059

Cited by 27 publications

(28 citation statements)

References 58 publications

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“…We speculate that this effect could be due to the local electric field induced by the excess charges that are excited with the laser pulse, which is also supported by DFT calculations. We believe that the observed temporal change of polarization in various solid-state quantum emitter systems is critical to reach the ideal performance of these emitters for several applications, such as to generate the Fouriertransform limited photons [41,42] or to achieve lower quantum bit error rate in quantum key distribution systems [27,43]. It might even be an important step toward achieving indistinguishable single photons from a room temperature solid-state quantum light source when coupled with resonant structures [44].…”

Section: Discussionmentioning

confidence: 99%

“…Before modeling the dipole characteristics theoretically for different defects, we first turn to investigate the temporal dynamics of polarization. This is particularly important in quantum technology applications, e.g., quantum key distribution with single photons which typically uses temporal filtering to improve the performance [27]. For studying the temporal dynamics of polarization, we have recorded the decay curve as a function of polarization using the same setup as for the other measurements above.…”

Section: Temporal Polarization Dynamicsmentioning

confidence: 99%

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Polarization dynamics of solid-state quantum emitters

Kumar¹,

Samaner²,

Cholsuk³

et al. 2023

Preprint

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Quantum emitters in solid-state crystals have recently attracted a lot of attention due to their simple applicability in optical quantum technologies. Color centers such as fluorescent defects hosted by diamond and hexagonal boron nitride (hBN) emit single photons at room temperature and can be used for nanoscale sensing. The atomic structure of the hBN defects, however, is not yet well understood. In this work, we fabricate an array of identical hBN emitters by localized electron irradiation. This allows us to correlate the dipole orientations with the host crystal axes. The angle of excitation and emission dipoles relative to the crystal axes are also calculated using density functional theory, which reveals characteristic angles for every specific defect. Moreover, we also investigate the temporal polarization dynamics and discover a mechanism of time-dependent polarization visibility and dipole orientation of color centers in hBN and diamond. This can be traced back to the excitation of excess charges in the local crystal environment. We therefore provide a promising pathway for the identification of color centers as well as important insight into the dynamics of solid-state quantum emitters.

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Section: Discussionmentioning

confidence: 99%

Section: Temporal Polarization Dynamicsmentioning

confidence: 99%

Polarization dynamics of solid-state quantum emitters

Kumar¹,

Samaner²,

Cholsuk³

et al. 2023

Preprint

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“…have been reported to date, covering all three telecom windows and different levels of device integration. Recently, also quantum emitters in hexagonal boron nitride (hBN) 52 as well as molecules of polyaromatic hydrocarbons 53 were considered and evaluated for their application in QKD, including an implementation of the B92 protocol 54 using an hBN-based SPS 55 . For our following comparison, we restrict ourselves to the state-of-the-art of BB84-QKD: the pioneering work by Waks et al 44 , which reported the largest secret key rate for quantum dot-based QKD to date, Leifgen et al 51 , evaluating nitrogen-and silicon-vacancy centers in diamond for QKD, and Takemoto et al 47 with the longest distance achieved for SPS-based QKD so far (c.f.…”

Section: Optimization and Benchmarkingmentioning

confidence: 99%

Atomically-thin single-photon sources for quantum communication

et al. 2023

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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 an emerging 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 click 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.

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“…The emission process was found to be radiation-tolerant, i.e., hBN quantum emitters can operate in space environments [41]. Single photons emitted from hBN have been utilized for use in quantum information processing [42,43], for extended quantum theory tests [18], and quantum key distribution [44]. The integration of hBN emitters with glass fibers where the emitter was placed onto the fiber facet has been demonstrated already [45].…”

Section: Quantum Photonics Modulementioning

confidence: 99%

QUICK$^3$ -- Design of a satellite-based quantum light source for quantum communication and extended physical theory tests in space

Ahmadi¹,

Schwertfeger²,

Werner³

et al. 2023

Preprint

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Modern quantum technologies have matured such that they can now be used in space applications, e.g., long-distance quantum communication. Here, we present the design of a compact true single photon source that can enhance the secure data rates in satellite-based quantum key distribution scenarios compared to conventional laser-based light sources. Our quantum light source is a fluorescent color center in hexagonal boron nitride. The emitter is off-resonantly excited by a diode laser and directly coupled to an integrated photonic processor that routes the photons to different experiments performed directly on-chip: (i) the characterization of the single photon source and (ii) testing a fundamental postulate of quantum mechanics, namely the relation of the probability density and the wave function (known as Born's rule). The described payload is currently being integrated into a 3U CubeSat and scheduled for launch in 2024 into low Earth orbit. We can therefore evaluate the feasibility of true single photon sources and reconfigurable photonic circuits in space. This provides a promising route toward a high-speed quantum network.

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

Cited by 27 publications

References 58 publications

Polarization dynamics of solid-state quantum emitters

Polarization dynamics of solid-state quantum emitters

Atomically-thin single-photon sources for quantum communication

QUICK$^3$ -- Design of a satellite-based quantum light source for quantum communication and extended physical theory tests in space

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