Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2311.13065 · Materials for Quantum Technology

On-demand quantum light sources for underwater communications

Dominic Scognamiglio, Angus Gale, Ali Al‐Juboori, Milos Toth, Igor Aharonovich

Published May 2, 2024• 7 citations
arXivHTMLPDF

Abstract

Abstract Quantum communication has been at the forefront of modern research for decades, however it is severely hampered in underwater applications, where the properties of water absorb nearly all useful optical wavelengths and prevent them from propagating more than, in most cases, a few metres. This research reports on-demand quantum light sources, suitable for underwater optical communication. The single photon emitters, which can be engineered using an electron beam, are based on impurities in hexagonal boron nitride. They have a zero phonon line at ∼436 nm, near the minimum value of water absorption and are shown to suffer negligible transmission and purity loss when travelling through water channels. These emitters are also shown to possess exceptional underwater transmission properties compared to emitters at other optical wavelengths and are utilised in a completely secure quantum key distribution experiment with rates of kbits s−1.

DOI
10.1088/2633-4356/ad46d7

Related papers

Coherent State Manipulation of Single Hexagonal Boron Nitride Quantum Emitters

Johann A. Preuß, Daniel Groll, Robert Schmidt +6 more

Single-photon sources are crucial components for building quantum networks and communications, but their optical coherent control remains a significant challenge in the development of quantum technologies. Recently, single-photon sources in atomically thin 2D materials such as transition metal dichalcogenides and van der Waals materials have emerged as promising solid-state quantum light emitters [1]. Hexagonal boron nitride (hBN) is a 2D insulator, which hosts optically active states in its band gap that efficiently emit single photons even at room temperature. The wide range of emission wavelengths, narrow emission lines, and convenient tunability of these hBN emitters make them particularly interesting for quantum sensing and wavelength division multiplexed quantum communications. They can also be found in commercially available nanocrystals, making them ideal for creating large arrays of single-photon emitters [2] and efficient coupling to photonic structures, such as 3D-printed microlenses [3].

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 26, 2023•0 citations

A proposal for a hybrid free-space optical quantum communication network with hexagonal boron nitride-based single photon sources

Julien Chénedé, Mostafa Abasifard, Tjorben Matthes +2 more

Hexagonal boron nitride (hBN) is known as a promising solid-state platform to host room temperature quantum emitters that produce high purity single photons. The bright and spectrally adaptable hBN emitters are space-compatible, making hBN well-suited for satellite-based free-space optical (FSO) quantum key distribution (QKD) at wavelengths where the atmospheric background is naturally suppressed. This paper presents a pathway to develop hBN emitters operating near the Ca-II Fraunhofer line (at 854 nm), enabling daylight FSO operation. Moreover, due to its compatibility with the first telecommunication window at 850 nm, it is possible to interface with optical fibers to bridge the `last mile' in a scenario where multiple end-users connect through a single optical ground station to a QKD satellite. We therefore introduce a concept that combines continuous operation of a quantum network, hybrid links to minimize deployment costs, and high data rates due to the use of realistic single photon sources. The realization would be an important milestone for the development of the quantum internet.

quant-pharXiv:2609.02229•IEEE International Instrumentation and Measurement Technology Conference•Sep 3, 2026•0 citations

Practical underwater quantum key distribution based on decoy-state BB84 protocol

Shanchuan Dong, Yonghe Yu, Shangshuai Zheng +4 more

Polarization encoding quantum key distribution has been proven to be a reliable method to build a secure communication system. It has already been used in an inter-city fiber channel and near-Earth atmosphere channel, leaving an underwater channel the last barrier to conquer. Here we demonstrate a decoy-state BB84 quantum key distribution system over a water channel with a compact system design for future experiments in the ocean. In the system, a multiple-intensity modulated laser module is designed to produce the light pulses of quantum states, including signal state, decoy state, and vacuum state. Classical communication and synchronization are realized by wireless optical transmission. Multiple filtering techniques and wavelength division multiplexing are further used to avoid cross talk of different lights. We test the performance of the system and obtain a final key rate of 245.6 bps with an average quantum bit error rate of 1.91% over a 2.4 m water channel, in which the channel attenuation is 16.35 dB. Numerical simulation shows that the system can tolerate up to 21.7 dB total channel loss and can still generate secure keys in 277.9 m Jerlov type I ocean channel.

arXiv:2203.04598•Applied Optics•May 3, 2022•5 citations

Channel analysis for single photon underwater free space quantum key distribution

Peng Shi, Shi-Cheng Zhao, Yongjian Gu +1 more

We investigate the optical absorption and scattering properties of underwater media pertinent to our underwater free space quantum key distribution (QKD) channel model. With the vector radiative transfer theory and Monte Carlo method, we obtain the attenuation of photons, the fidelity of the scattered photons, the quantum bit error rate, and the sifted key generation rate of underwater quantum communication. It can be observed from our simulations that the most secure single photon underwater free space QKD is feasible in the clearest ocean water.

arXiv:1402.4666•Journal of the Optical Society of America A•Jan 30, 2015•50 citations

Integrated Room Temperature Single Photon Source for Quantum Key Distribution

Helen Zhi Jie Zeng, Minh Anh Phan Ngyuen, Ai, Xiaoyu +8 more

High-purity single photon sources (SPS) that can operate at room temperature are highly desirable for a myriad of applications, including quantum photonics and quantum key distribution. In this work, we realise an ultra-bright solid-state SPS based on an atomic defect in hexagonal boron nitride (hBN) integrated with a solid immersion lens (SIL). The SIL increases the source efficiency by a factor of six, and the integrated system is capable of producing over ten million single photons per second at room temperature. Our results are promising for practical applications of SPS in quantum communication protocols.

arXiv:2201.11882•Jan 28, 2022•0 citations

QUICK3$^3$ ‐ Design of a Satellite‐Based Quantum Light Source for Quantum Communication and Extended Physical Theory Tests in Space

Najme Ahmadi, S. Schwertfeger, Philipp Werner +19 more

Abstract Modern quantum technologies have matured such that they can now be used in space applications, e.g., long‐distance quantum communication. Here, the design of a compact true single photon source is presented that can enhance the secure data rates in satellite‐based quantum key distribution scenarios compared to conventional laser‐based light sources. The 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 to launch in 2024 into low Earth orbit. Therefore the feasibility of true single photon sources and reconfigurable photonic circuits in space can be evaluated. This provides a promising route toward a high‐speed quantum network.

arXiv:2301.11177•Advanced Quantum Technologies•Jan 21, 2024•29 citations
Abstract Quantum communication has been at the forefront of modern research for decades, however it is severely hampered in underwater applications, where the properties of water absorb nearly all useful optical wavelengths and prevent them from propagating more than, in most cases, a few metres. This research reports on-demand quantum light sources, suitable for underwater optical communication. The single photon emitters, which can be engineered using an electron beam, are based on impurities in hexagonal boron nitride. They have a zero phonon line at ∼436 nm, near the minimum value of water absorption and are shown to suffer negligible transmission and purity loss when travelling through water channels. These emitters are also shown to possess exceptional underwater transmission properties compared to emitters at other optical wavelengths and are utilised in a completely secure quantum key distribution experiment with rates of kbits s−1.
Single-photon sources are crucial components for building quantum networks and communications, but their optical coherent control remains a significant challenge in the development of quantum technologies. Recently, single-photon sources in atomically thin 2D materials such as transition metal dichalcogenides and van der Waals materials have emerged as promising solid-state quantum light emitters [1]. Hexagonal boron nitride (hBN) is a 2D insulator, which hosts optically active states in its band gap that efficiently emit single photons even at room temperature. The wide range of emission wavelengths, narrow emission lines, and convenient tunability of these hBN emitters make them particularly interesting for quantum sensing and wavelength division multiplexed quantum communications. They can also be found in commercially available nanocrystals, making them ideal for creating large arrays of single-photon emitters [2] and efficient coupling to photonic structures, such as 3D-printed microlenses [3].
Hexagonal boron nitride (hBN) is known as a promising solid-state platform to host room temperature quantum emitters that produce high purity single photons. The bright and spectrally adaptable hBN emitters are space-compatible, making hBN well-suited for satellite-based free-space optical (FSO) quantum key distribution (QKD) at wavelengths where the atmospheric background is naturally suppressed. This paper presents a pathway to develop hBN emitters operating near the Ca-II Fraunhofer line (at 854 nm), enabling daylight FSO operation. Moreover, due to its compatibility with the first telecommunication window at 850 nm, it is possible to interface with optical fibers to bridge the `last mile' in a scenario where multiple end-users connect through a single optical ground station to a QKD satellite. We therefore introduce a concept that combines continuous operation of a quantum network, hybrid links to minimize deployment costs, and high data rates due to the use of realistic single photon sources. The realization would be an important milestone for the development of the quantum internet.
Polarization encoding quantum key distribution has been proven to be a reliable method to build a secure communication system. It has already been used in an inter-city fiber channel and near-Earth atmosphere channel, leaving an underwater channel the last barrier to conquer. Here we demonstrate a decoy-state BB84 quantum key distribution system over a water channel with a compact system design for future experiments in the ocean. In the system, a multiple-intensity modulated laser module is designed to produce the light pulses of quantum states, including signal state, decoy state, and vacuum state. Classical communication and synchronization are realized by wireless optical transmission. Multiple filtering techniques and wavelength division multiplexing are further used to avoid cross talk of different lights. We test the performance of the system and obtain a final key rate of 245.6 bps with an average quantum bit error rate of 1.91% over a 2.4 m water channel, in which the channel attenuation is 16.35 dB. Numerical simulation shows that the system can tolerate up to 21.7 dB total channel loss and can still generate secure keys in 277.9 m Jerlov type I ocean channel.
We investigate the optical absorption and scattering properties of underwater media pertinent to our underwater free space quantum key distribution (QKD) channel model. With the vector radiative transfer theory and Monte Carlo method, we obtain the attenuation of photons, the fidelity of the scattered photons, the quantum bit error rate, and the sifted key generation rate of underwater quantum communication. It can be observed from our simulations that the most secure single photon underwater free space QKD is feasible in the clearest ocean water.
High-purity single photon sources (SPS) that can operate at room temperature are highly desirable for a myriad of applications, including quantum photonics and quantum key distribution. In this work, we realise an ultra-bright solid-state SPS based on an atomic defect in hexagonal boron nitride (hBN) integrated with a solid immersion lens (SIL). The SIL increases the source efficiency by a factor of six, and the integrated system is capable of producing over ten million single photons per second at room temperature. Our results are promising for practical applications of SPS in quantum communication protocols.
QUICK33^33 ‐ Design of a Satellite‐Based Quantum Light Source for Quantum Communication and Extended Physical Theory Tests in Space
Abstract Modern quantum technologies have matured such that they can now be used in space applications, e.g., long‐distance quantum communication. Here, the design of a compact true single photon source is presented that can enhance the secure data rates in satellite‐based quantum key distribution scenarios compared to conventional laser‐based light sources. The 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 to launch in 2024 into low Earth orbit. Therefore the feasibility of true single photon sources and reconfigurable photonic circuits in space can be evaluated. This provides a promising route toward a high‐speed quantum network.