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:2609.37244

L-band single-photon generation from a cavity-coupled silicon C-center

Carolina Crosta, Kyu-Young Kim, Purbita Purkayastha, Abhijit Biswas, Jasvith Raj Basani, Amirehsan Alizadehherfati, Amirehsan Boreiri, Chang-Min Lee, Fabio Pezzoli, Edo Waks

quant-phcond-mat.mtrl-sciSubmitted Sep 29, 2026• Announced Sep 30, 2026• 0 citations
arXivHTMLPDF

Abstract

Monolithic integration of single-photon sources into silicon photonics offers a compelling solution for realizing scalable quantum telecommunication architectures. Among the candidate silicon color centers, the C-center features a zero-phonon emission in the telecom L-band, corresponding to the spectral window of minimum transmission loss in optical fibers. Despite this advantage, isolating single C-centers has remained an unrealized challenge in solid-state quantum optics. In this work, we report the isolation of a single silicon C-center. We enhance the spontaneous emission rate of the zero-phonon line by coupling the single emitter to a nanophotonic crystal cavity, observing a fivefold reduction in the excited-state lifetime compared to bulk conditions, which corresponds to a Purcell factor lower bound of 33. Second-order autocorrelation measurements confirm single-photon emission from the investigated defect, obtaining an optical purity of $g^{(2)}(0) = 0.23$ without background correction. Our results establish a native telecom L-band quantum light source in silicon, laying the foundation for ultra-low-loss and long-distance quantum applications.

Related papers

Purcell Enhancement of a single T center in a silicon nanophotonic cavity

Johnston, Adam

Implementation of large-scale quantum networks have the potential to augment the capabilities of existing quantum information technologies. By linking quantum processors over photonic channels, future quantum networks could enable applications such as remote quantum sensing, distributed quantum computing, and secure quantum communication. Atomic defects in solids are readily integrated with photonic structures, making them promising candidates for use in quantum networking devices. In particular, the silicon material platform holds great promise due to the technologically mature silicon electronic and photonic industries. The T center defects in silicon possess telecom O-band optical transitions, as well as long-lived electronic and nuclear spins, making it the focus of particular interest. These spin and optical properties of single T centers, together with their accessibility to the existing integrated electronic and photonic technologies, opening the door to modular long-distance quantum networking technologies built on the T center platform. This work outlines the integration of single T centers with a silicon photonic crystal cavity; we observe cavity-enhanced fluorescence emission, resulting in a decay rate enhancement factor of F = 6.89 compared to the bulk emission rate. Through the use of silicon photonic circuits and an angle-polished fiber for light coupling, we achieve a maximum zero phonon line photon outcoupling rate of 73.3 kHz. The design and fabrication of the nanophotonic cavity used in experiment is detailed. This work represents a major step towards use of the silicon T center as a telecom spin-photon interface in future quantum networking applications.

•Jul 25, 2024•0 citations

Bright Purcell-Enhanced Single Photon Emission from a Silicon G Center

Kyu-Young Kim, Chang-Min Lee, Amirehsan Boreiri +5 more

Silicon G centers show significant promise as single photon sources in a scalable silicon platform. But these color centers have large nonradiative decay and a low Debye-Waller factor, limiting their usability in quantum applications. In this work, we demonstrate bright Purcell-enhanced emission from a silicon G center by coupling it to a nanophotonic cavity. The nanobeam cavity enhances the spontaneous emission rate of a single G center by a factor of 6, corresponding to a Purcell factor greater than 31 when accounting for decay into the phonon sideband. We obtain a spontaneous emission rate of 0.97 ns, which is the fastest single photon emission rate reported in silicon. With this radiative enhancement, we achieve an order of magnitude improvement in emitter brightness compared to previously reported values. These results pave the way for scalable quantum light sources on a silicon photonic chip.

arXiv:2412.10603•Nano Letters•Mar 11, 2025•10 citations

Strongly Cavity-Enhanced Spontaneous Emission from Silicon-Vacancy Centers in Diamond

Jingyuan Linda Zhang, Shuo Sun, Michael J. Burek +11 more

Quantum emitters are an integral component for a broad range of quantum technologies, including quantum communication, quantum repeaters, and linear optical quantum computation. Solid-state color centers are promising candidates for scalable quantum optics due to their long coherence time and small inhomogeneous broadening. However, once excited, color centers often decay through phonon-assisted processes, limiting the efficiency of single-photon generation and photon-mediated entanglement generation. Herein, we demonstrate strong enhancement of spontaneous emission rate of a single silicon-vacancy center in diamond embedded within a monolithic optical cavity, reaching a regime in which the excited-state lifetime is dominated by spontaneous emission into the cavity mode. We observe 10-fold lifetime reduction and 42-fold enhancement in emission intensity when the cavity is tuned into resonance with the optical transition of a single silicon-vacancy center, corresponding to 90% of the excited-state energy decay occurring through spontaneous emission into the cavity mode. We also demonstrate the largest coupling strength (g/2π = 4.9 ± 0.3 GHz) and cooperativity (C = 1.4) to date for color-center-based cavity quantum electrodynamics systems, bringing the system closer to the strong coupling regime.

arXiv:1708.05771•Nano Letters•Jan 29, 2018•152 citations

Bright Telecom Spin-Photon Interface in Silicon Photonics

Carolina Crosta, Amirehsan Alizadehherfati, Purbita Purkayastha +5 more

Silicon is an attractive host for scalable quantum photonics, but the absence of bright telecom-band emitters with optically addressable spin states has limited its use for spin-photon interfaces. Here we demonstrate the Al1-center, an aluminum--carbon defect in silicon, as a bright waveguide-integrated single-photon emitter with a ground-state spin. Using isotopically purified silicon-on-insulator nanophotonic devices, we isolate individual Al1-centers and observe high-purity single-photon emission with $g^{(2)}(0)=0.04$ without background subtraction. Time-resolved photoluminescence spectroscopy reveals a fast excited-state lifetime of 135 ns, nearly an order of magnitude shorter than the benchmark provided by the well-studied T-center. Resonant photoluminescence excitation measurements further resolve the zero-phonon transition and reveal a narrow homogeneous linewidth reaching 47 MHz, threefold narrower than the T-center under comparable temperature. Through magneto-optical spectroscopy, we resolve the spin-dependent transitions of the bound-exciton manifold and achieve spin-selective optical pumping, fulfilling the prerequisite for quantum state initialization and readout. These results establish the Al1-center as a bright telecom-band spin-photon interface in silicon photonics and introduce a promising platform for integrated quantum networks.

quant-pharXiv:2607.18435•Jul 22, 2026

Cavity-coupled telecom atomic source in silicon

Adam Johnston, Ulises Felix-Rendon, Yu-En Wong +1 more

Novel T centers in silicon hold great promise for quantum networking applications due to their telecom band optical transitions and the long-lived ground state electronic spins. An open challenge for advancing the T center platform is to enhance its weak and slow zero phonon line (ZPL) emission. In this work, by integrating single T centers with a low-loss, small mode-volume silicon photonic crystal cavity, we demonstrate an enhancement of the fluorescence decay rate by a factor of F = 6.89. Efficient photon extraction enables the system to achieve an average ZPL photon outcoupling rate of 73.3 kHz under saturation, which is about two orders of magnitude larger than the previously reported value. The dynamics of the coupled system is well modeled by solving the Lindblad master equation. These results represent a significant step towards building efficient T center spin-photon interfaces for quantum information processing and networking applications.

arXiv:2310.20014•Nature Communications•Mar 15, 2024•53 citations

Cavity-enhanced single artificial atoms in silicon

Valeria Saggio, Carlos Errando-Herranz, Samuel Gyger +9 more

Artificial atoms in solids are leading candidates for quantum networks, scalable quantum computing, and sensing, as they combine long-lived spins with mobile photonic qubits. Recently, silicon has emerged as a promising host material where artificial atoms with long spin coherence times and emission into the telecommunications band can be controllably fabricated. This field leverages the maturity of silicon photonics to embed artificial atoms into the world's most advanced microelectronics and photonics platform. However, a current bottleneck is the naturally weak emission rate of these atoms, which can be addressed by coupling to an optical cavity. Here, we demonstrate cavity-enhanced single artificial atoms in silicon (G-centers) at telecommunication wavelengths. Our results show enhancement of their zero phonon line intensities along with highly pure single-photon emission, while their lifetime remains statistically unchanged. We suggest the possibility of two different existing types of G-centers, shedding new light on the properties of silicon emitters.

Nature Communications•Jun 21, 2024•40 citations
Monolithic integration of single-photon sources into silicon photonics offers a compelling solution for realizing scalable quantum telecommunication architectures. Among the candidate silicon color centers, the C-center features a zero-phonon emission in the telecom L-band, corresponding to the spectral window of minimum transmission loss in optical fibers. Despite this advantage, isolating single C-centers has remained an unrealized challenge in solid-state quantum optics. In this work, we report the isolation of a single silicon C-center. We enhance the spontaneous emission rate of the zero-phonon line by coupling the single emitter to a nanophotonic crystal cavity, observing a fivefold reduction in the excited-state lifetime compared to bulk conditions, which corresponds to a Purcell factor lower bound of 33. Second-order autocorrelation measurements confirm single-photon emission from the investigated defect, obtaining an optical purity of g(2)(0)=0.23g^{(2)}(0) = 0.23g(2)(0)=0.23 without background correction. Our results establish a native telecom L-band quantum light source in silicon, laying the foundation for ultra-low-loss and long-distance quantum applications.
Implementation of large-scale quantum networks have the potential to augment the capabilities of existing quantum information technologies. By linking quantum processors over photonic channels, future quantum networks could enable applications such as remote quantum sensing, distributed quantum computing, and secure quantum communication. Atomic defects in solids are readily integrated with photonic structures, making them promising candidates for use in quantum networking devices. In particular, the silicon material platform holds great promise due to the technologically mature silicon electronic and photonic industries. The T center defects in silicon possess telecom O-band optical transitions, as well as long-lived electronic and nuclear spins, making it the focus of particular interest. These spin and optical properties of single T centers, together with their accessibility to the existing integrated electronic and photonic technologies, opening the door to modular long-distance quantum networking technologies built on the T center platform. This work outlines the integration of single T centers with a silicon photonic crystal cavity; we observe cavity-enhanced fluorescence emission, resulting in a decay rate enhancement factor of F = 6.89 compared to the bulk emission rate. Through the use of silicon photonic circuits and an angle-polished fiber for light coupling, we achieve a maximum zero phonon line photon outcoupling rate of 73.3 kHz. The design and fabrication of the nanophotonic cavity used in experiment is detailed. This work represents a major step towards use of the silicon T center as a telecom spin-photon interface in future quantum networking applications.
Silicon G centers show significant promise as single photon sources in a scalable silicon platform. But these color centers have large nonradiative decay and a low Debye-Waller factor, limiting their usability in quantum applications. In this work, we demonstrate bright Purcell-enhanced emission from a silicon G center by coupling it to a nanophotonic cavity. The nanobeam cavity enhances the spontaneous emission rate of a single G center by a factor of 6, corresponding to a Purcell factor greater than 31 when accounting for decay into the phonon sideband. We obtain a spontaneous emission rate of 0.97 ns, which is the fastest single photon emission rate reported in silicon. With this radiative enhancement, we achieve an order of magnitude improvement in emitter brightness compared to previously reported values. These results pave the way for scalable quantum light sources on a silicon photonic chip.
Quantum emitters are an integral component for a broad range of quantum technologies, including quantum communication, quantum repeaters, and linear optical quantum computation. Solid-state color centers are promising candidates for scalable quantum optics due to their long coherence time and small inhomogeneous broadening. However, once excited, color centers often decay through phonon-assisted processes, limiting the efficiency of single-photon generation and photon-mediated entanglement generation. Herein, we demonstrate strong enhancement of spontaneous emission rate of a single silicon-vacancy center in diamond embedded within a monolithic optical cavity, reaching a regime in which the excited-state lifetime is dominated by spontaneous emission into the cavity mode. We observe 10-fold lifetime reduction and 42-fold enhancement in emission intensity when the cavity is tuned into resonance with the optical transition of a single silicon-vacancy center, corresponding to 90% of the excited-state energy decay occurring through spontaneous emission into the cavity mode. We also demonstrate the largest coupling strength (g/2π = 4.9 ± 0.3 GHz) and cooperativity (C = 1.4) to date for color-center-based cavity quantum electrodynamics systems, bringing the system closer to the strong coupling regime.
Silicon is an attractive host for scalable quantum photonics, but the absence of bright telecom-band emitters with optically addressable spin states has limited its use for spin-photon interfaces. Here we demonstrate the Al1-center, an aluminum--carbon defect in silicon, as a bright waveguide-integrated single-photon emitter with a ground-state spin. Using isotopically purified silicon-on-insulator nanophotonic devices, we isolate individual Al1-centers and observe high-purity single-photon emission with g(2)(0)=0.04g^{(2)}(0)=0.04g(2)(0)=0.04 without background subtraction. Time-resolved photoluminescence spectroscopy reveals a fast excited-state lifetime of 135 ns, nearly an order of magnitude shorter than the benchmark provided by the well-studied T-center. Resonant photoluminescence excitation measurements further resolve the zero-phonon transition and reveal a narrow homogeneous linewidth reaching 47 MHz, threefold narrower than the T-center under comparable temperature. Through magneto-optical spectroscopy, we resolve the spin-dependent transitions of the bound-exciton manifold and achieve spin-selective optical pumping, fulfilling the prerequisite for quantum state initialization and readout. These results establish the Al1-center as a bright telecom-band spin-photon interface in silicon photonics and introduce a promising platform for integrated quantum networks.
Novel T centers in silicon hold great promise for quantum networking applications due to their telecom band optical transitions and the long-lived ground state electronic spins. An open challenge for advancing the T center platform is to enhance its weak and slow zero phonon line (ZPL) emission. In this work, by integrating single T centers with a low-loss, small mode-volume silicon photonic crystal cavity, we demonstrate an enhancement of the fluorescence decay rate by a factor of F = 6.89. Efficient photon extraction enables the system to achieve an average ZPL photon outcoupling rate of 73.3 kHz under saturation, which is about two orders of magnitude larger than the previously reported value. The dynamics of the coupled system is well modeled by solving the Lindblad master equation. These results represent a significant step towards building efficient T center spin-photon interfaces for quantum information processing and networking applications.
Artificial atoms in solids are leading candidates for quantum networks, scalable quantum computing, and sensing, as they combine long-lived spins with mobile photonic qubits. Recently, silicon has emerged as a promising host material where artificial atoms with long spin coherence times and emission into the telecommunications band can be controllably fabricated. This field leverages the maturity of silicon photonics to embed artificial atoms into the world's most advanced microelectronics and photonics platform. However, a current bottleneck is the naturally weak emission rate of these atoms, which can be addressed by coupling to an optical cavity. Here, we demonstrate cavity-enhanced single artificial atoms in silicon (G-centers) at telecommunication wavelengths. Our results show enhancement of their zero phonon line intensities along with highly pure single-photon emission, while their lifetime remains statistically unchanged. We suggest the possibility of two different existing types of G-centers, shedding new light on the properties of silicon emitters.