© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

arXiv:2103.17209 · Physical Review Research

Sensitive single-photon test of extended quantum theory with two-dimensional hexagonal boron nitride

Tobias Vogl, Heiko Knopf, Maximilian A. Weissflog, Ping Koy Lam, Falk X. Eilenberger

Published Mar 31, 2021• 32 citations

Abstract

Quantum theory is the foundation of modern physics.Some of its basic principles, such as Born's rule, however, are based on postulates which require experimental testing.Any deviation from Born's rule would result in higher-order interference and can thus be tested in an experiment.Here, we report on such a test with a quantum light source based on a color center in hexagonal boron nitride (hBN) coupled to a microcavity.Our room-temperature photon source features a narrow-linewidth, high-efficiency, high-purity, and on-demand single-photon generation.With the single-photon source we can increase the interferometric sensitivity of our three-path interferometer compared to conventional laser-based light sources by fully suppressing the detector nonlinearity.We thereby obtain a tight bound on the third-order interference term of 3.96(523) × 10 -4 .We also measure an interference visibility of 98.58% for our single photons emitted from hBN at room temperature, which provides a promising route for using the hBN platform as light source for phase-encoding schemes in quantum key distribution.

DOI: 10.1103/physrevresearch.3.013296

Related papers

Compact Cavity-Enhanced Single-Photon Generation with Hexagonal Boron Nitride

Tobias Vogl, Ruvi Lecamwasam, B. C. Buchler +2 more

Sources of pure and indistinguishable single-photons are critical for near-future optical quantum technologies. Recently, color centers hosted by two-dimensional hexagonal boron nitride (hBN) have emerged as a promising platform for high luminosity room temperature single-photon sources. Despite the brightness of the emitters, the spectrum is rather broad and the single-photon purity is not sufficient for practical quantum information processing. Here, we report integration of such a quantum emitter hosted by hBN into a tunable optical microcavity. A small mode volume of the order of λ 3 allows us to Purcell enhance the fluorescence, with the observed excited state lifetime shortening. The cavity significantly narrows the spectrum and improves the single-photon purity by suppression of off-resonant noise. The complete device, including all optics, driving electronics, and control units, is compact and integrated in a small volume of 10 × 10 × 10 cm 3, allowing for portable usage in mobile applications.

arXiv:1902.03019•ACS Photonics•Jun 26, 2019•147 citations

Satellite-based quantum communication and extended physical theory tests in space

Josefine Krause, Mohammad N. Mishuk, Najme Ahmadi +4 more

We present a compact room temperature single photon source based on a color center in hexagonal boron nitride for future long-distance satellite-based quantum networks. The performance of this quantum light source is sufficient to outperform state-of-the-art laser-based decoy quantum key distribution protocols. The emitter is directly coupled to a photonic integrated circuit that routes the single photons to different experiments. This includes both a verification of the single photon source via measuring the photon statistics, as well as a fundamental test extended quantum theory in microgravity. The payload is currently being integrated on a 3U CubeSat and will be launched in 2024 as part of the QUICK3 mission.

Emerging Imaging and Sensing Technologies for Security and Defence•Oct 17, 2023•0 citations

Integrated Room Temperature Single Photon Source in Hexagonal Boron Nitride for Quantum Key Distribution

Helen Zhi Jie Zeng, Ali Al‐Juboori, Minh Nguyen +8 more

Quantum Key Distribution (QKD) is important for a variety of quantum technologies. Here we demonstrate a free-space room temperature, discreet-variable QKD system using a bright Single photon sources (SPS) in hexagonal Boron Nitride (hBN).

•Jan 1, 2024•0 citations

Integrated room temperature single-photon source for quantum key distribution

Helen Zhi Jie Zeng, Minh Anh Phan Ngyuen, Xiaoyu Ai +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 realize 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.

Optics Letters•Feb 22, 2022•43 citations

Next-generation single photon sources for satellite-based quantum communication

Tobias Vogl, Sebastian Ritter, Mostafa Abasifard +3 more

We present a room temperature single photon source based on a color center in hexagonal boron nitride for satellite-based quantum networks. The resonator-coupled emitter is characterized by a narrowband tuneable spectrum, high photon purity, and high quantum efficiency. The photon source is currently integrated on a 3U CubeSat to qualify it for use in a future satellite-based global quantum-encrypted network. The satellite also performs a fundamental test of quantum gravity.

Advanced Photon Counting Techniques•May 27, 2022•0 citations

Room-temperature single-photon sources using solid-state emitters and open-access microcavities (Conference Presentation)

Sanmi Adekanye, Philip R. Dolan, Aurelien A. P. Trichet +2 more

Single photons are the key ingredient for many photonic quantum technologies including quantum key distribution and measurement-based quantum computing. However, it remains difficult to create devices with the appropriate specifications for use in non-laboratory environments. The optical microcavity platform provides an attractive route towards a room temperature single photon source device. Our ultra-small focused ion beam (FIB) milled open-access cavities offer enhancement of the spontaneous emission rate, tunability of the emission spectrum and increased light collection. The embedment of solid-state emitters within these cavities enables us to create a robust room temperature single photon source device, with the potential for high efficiencies and single photon purities. Defects such as the nitrogen-vacancy (NV) centre in diamond have been shown to be stable room-temperature sources of single photons. There are new single emitters emerging in two-dimensional materials such as hexagonal boron nitride (hBN). Here we present developments in room-temperature coupling of single defects to open-access microcavities of a planar-hemispherical geometry with mode volumes down to λ3. We report enhancements in the spectral density of photons into a single cavity mode, combined with improved single photon purities. It will be shown that the NV-cavity system provides a ~3% single photon emission efficiency with purities of up to 94%. The hBN-cavity system provides count rates >1Mcts/s into a single cavity mode with purities up to 96%. With these high single photon purities, such devices would be robust against photon number splitting attacks making them attractive for applications in quantum cryptography.

Quantum Computing, Communication, and Simulation•Mar 14, 2018•0 citations

Quantum theory is the foundation of modern physics.Some of its basic principles, such as Born's rule, however, are based on postulates which require experimental testing.Any deviation from Born's rule would result in higher-order interference and can thus be tested in an experiment.Here, we report on such a test with a quantum light source based on a color center in hexagonal boron nitride (hBN) coupled to a microcavity.Our room-temperature photon source features a narrow-linewidth, high-efficiency, high-purity, and on-demand single-photon generation.With the single-photon source we can increase the interferometric sensitivity of our three-path interferometer compared to conventional laser-based light sources by fully suppressing the detector nonlinearity.We thereby obtain a tight bound on the third-order interference term of 3.96(523) × 10 -4 .We also measure an interference visibility of 98.58% for our single photons emitted from hBN at room temperature, which provides a promising route for using the hBN platform as light source for phase-encoding schemes in quantum key distribution.

Sources of pure and indistinguishable single-photons are critical for near-future optical quantum technologies. Recently, color centers hosted by two-dimensional hexagonal boron nitride (hBN) have emerged as a promising platform for high luminosity room temperature single-photon sources. Despite the brightness of the emitters, the spectrum is rather broad and the single-photon purity is not sufficient for practical quantum information processing. Here, we report integration of such a quantum emitter hosted by hBN into a tunable optical microcavity. A small mode volume of the order of λ 3 allows us to Purcell enhance the fluorescence, with the observed excited state lifetime shortening. The cavity significantly narrows the spectrum and improves the single-photon purity by suppression of off-resonant noise. The complete device, including all optics, driving electronics, and control units, is compact and integrated in a small volume of 10 × 10 × 10 cm 3, allowing for portable usage in mobile applications.

We present a compact room temperature single photon source based on a color center in hexagonal boron nitride for future long-distance satellite-based quantum networks. The performance of this quantum light source is sufficient to outperform state-of-the-art laser-based decoy quantum key distribution protocols. The emitter is directly coupled to a photonic integrated circuit that routes the single photons to different experiments. This includes both a verification of the single photon source via measuring the photon statistics, as well as a fundamental test extended quantum theory in microgravity. The payload is currently being integrated on a 3U CubeSat and will be launched in 2024 as part of the QUICK3 mission.

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 realize 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.

Single photons are the key ingredient for many photonic quantum technologies including quantum key distribution and measurement-based quantum computing. However, it remains difficult to create devices with the appropriate specifications for use in non-laboratory environments. The optical microcavity platform provides an attractive route towards a room temperature single photon source device. Our ultra-small focused ion beam (FIB) milled open-access cavities offer enhancement of the spontaneous emission rate, tunability of the emission spectrum and increased light collection. The embedment of solid-state emitters within these cavities enables us to create a robust room temperature single photon source device, with the potential for high efficiencies and single photon purities. Defects such as the nitrogen-vacancy (NV) centre in diamond have been shown to be stable room-temperature sources of single photons. There are new single emitters emerging in two-dimensional materials such as hexagonal boron nitride (hBN). Here we present developments in room-temperature coupling of single defects to open-access microcavities of a planar-hemispherical geometry with mode volumes down to λ3. We report enhancements in the spectral density of photons into a single cavity mode, combined with improved single photon purities. It will be shown that the NV-cavity system provides a ~3% single photon emission efficiency with purities of up to 94%. The hBN-cavity system provides count rates >1Mcts/s into a single cavity mode with purities up to 96%. With these high single photon purities, such devices would be robust against photon number splitting attacks making them attractive for applications in quantum cryptography.