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:1901.05371 · Physical Review Applied

Optical Properties of Vanadium in 4 H Silicon Carbide for Quantum Technology

Lukas Spindlberger, A. Csóré, Gergő Thiering, Stefan Putz, R. Karhu, J.Ul Hassan, N.T. Son, T. Fromherz, A. Gali, Michael Trupke

Published Jul 9, 2019• 82 citations
arXivHTMLPDF

Abstract

Light emission stemming from V impurities in $4H$-SiC is recorded at 1.28 and 1.33 $\ensuremath{\mu}$m, in the telecommunication $O$ band, which gives hope for the creation of efficient single-photon sources in existing telecommunication networks, ultimately paving the way for secure long-range quantum communication networks. Combined with the available electronic and nuclear degrees of freedom, vanadium presents all of the required ingredients for a highly efficient spin-photon interface. These V centers are reminiscent of the Mo defect in SiC and the Si-$V$ complex in diamond, but work at practical wavelengths for telecommunication.

DOI
10.1103/physrevapplied.12.014015

Related papers

A Si-on-SiC Platform for Interfacing with Vanadium Dopants in the Telecom O-Band

Timothy Draher, Nolan Bitner, Vasileios Niaouris +6 more

Vanadium color centers in silicon carbide (SiC) offer telecom O-band emission, sub-microsecond optical lifetimes, and second-scale spin relaxation times, rendering them promising candidates for quantum network nodes. However, efficient photon extraction from the high-refractive-index SiC host remains challenging. Here, we introduce a silicon-on-SiC heterogeneous photonic platform in which silicon nanocavities evanescently couple to shallow vanadium dopants in commercial 4H-SiC, enabling efficient zero-phonon line (ZPL) collection under resonant excitation. In as-grown ensembles, we observe Purcell-enhanced photoluminescence with transient spectral hole burning linewidths of 50 MHz on microsecond timescales. In dilute implanted samples, we isolate individual vanadium centers with high-purity single photon emission and a Purcell-enhanced lifetime of 109 ns. The entire optical interface operates through a single lensed fiber, including a 905 nm repump laser that recovers the vanadium charge state with 95% efficiency. These results establish Si-on-SiC as a scalable, foundry-compatible platform for telecom-wavelength spin-photon interfaces.

cond-mat.mtrl-sciCross-listedarXiv:2609.35702•Sep 29, 2026

Optical Spin-Photon Interfaces with a Focus on Transition Metal Defects in Silicon Carbide

Benedikt Tissot

The conversion between stationary and flying qubits is a pillar of numerous quantum technologies such as distributed quantum computing as well as many quantum internet and networking protocols. These quantum technologies promise to use resources, in particular entanglement, not available to classical devices to accomplish tasks that are difficult or even impossible to realize with classical devices. Applications range from fundamental research to secure communication. Because some of these applications require the generation of entanglement, even over large distances, there is substantial interest in efficient interfaces between flying qubits, usually photons, and a stationary memory. In this thesis, we evaluate key aspects of optical spin-photon interfaces, a class of devices combining a stationary qubit memory (spins) and an interface with flying qubits (photons). We focus on defects in silicon carbide (SiC) in which a transition metal (TM) atom substitutes a silicon (Si) atom in the lattice, so that the energy levels with naturally bound quantum states localized around the defect lie within the band gap of SiC. We highlight two key properties of these defects as stationary-flying interconnects: First, they have favorable spin coherence properties and the pertaining nuclear spin of the TM can be used as a quantum memory. Second, they feature a localized and efficient spin-photon interface via their excited states. Defects where vanadium takes the place of a Si atom even allow for photon emission with frequencies in one of the fiber-optic transmission windows, which support efficient transmission in optical fiber. Our results are readily combined with numerical ab-initio and experimental data, providing intuition and further insight into the underlying physics. Additionally, the theoretical assessments of this thesis bridge the gap between the fundamental characterization of TM defects in SiC and their use as spin-photon interfaces in future experiments and quantum technology applications. For instance, the proposed nuclear-spin preparation protocol and spin control mark the first step towards an all-optically controlled integrated platform for quantum technology with TM defects in SiC.

•Jan 1, 2023•0 citations

Extended spin relaxation times of optically addressed vanadium defects in silicon carbide at telecommunication frequencies

Jonghoon Ahn, Christina Wicker, Nolan Bitner +7 more

Spin defects embedded in a scalable material platform with bright telecom emission are promising candidates for quantum communication technologies. ${V}^{4+}$ in SiC fulfills these criteria, but its potential is limited by the lack of understanding of its spin relaxation mechanisms. This study employs all-optical measurements to reveal that the site-dependent spin ${T}_{1}$ values can exceed 20 seconds and identifies the mechanism of the spin relaxation processes. These insights lead to a proposal to enable qubit operations at higher temperatures, significantly reducing the infrastructure requirements and paving the way for practical realization of quantum technologies based on ${V}^{4+}$ in SiC.

Physical Review Applied•Oct 29, 2024•15 citations

Silicon carbide: A promising platform for scalable quantum networks

Yu Zhou, Junhua Tan, Haojun Hu +9 more

Quantum networks based on solid-state spin defects present a transformative approach to secure communication and distributed quantum computing, utilizing quantum entanglement and coherent spin–photon interfaces. Silicon carbide (SiC) stands out as a compelling material platform due to its unique combination of a wide bandgap, high optical nonlinearity, CMOS-compatible fabrication, and controllable spin-active defects. These intrinsic properties facilitate efficient photon emission, robust spin coherence at both room and cryogenic temperatures, and integration with photonic nanostructures. Recent advancements in defect engineering and micro-nanophotonics have unlocked the potential of SiC quantum nodes, which feature electron-nuclear spin systems for high-fidelity quantum operations and long-lived quantum memories. Key steps such as single-shot readout and spin-photon entanglement have been successfully demonstrated, bringing SiC closer to a real quantum network platform. This review offers a comprehensive overview of the advancements in SiC-based quantum networks, encompassing key aspects such as defect fabrication methodologies, optimization of spin-photon interfaces, and strategies for photonic integration. Additionally, it examines the existing challenges and outlines promising future directions in this rapidly evolving field.

Applied Physics Reviews•Jul 1, 2025•18 citations

Telecom-band quantum memory with chlorine defects in silicon carbide

A. N. Anisimov, K. Mavridou, A. V. Mathews +2 more

Realization of quantum memory with a photonic interface in the telecommunication bands in a wafer-scalable platform is a central requirement for long-distance quantum networks. Silicon carbide (SiC) provides a technologically mature host for integrated quantum photonics, yet only a limited number of defects combine spin functionality with telecom emission. Here we report on chlorine-based defects in 4H-SiC as a platform for telecom-band quantum memory. The emission of these defects spans the entire telecommunication range with zero-phonon lines in the O- and C-bands and a Debye-Waller factor of up to $39 \, \%$. Time-resolved photoluminescence measurements reveal a short excited-state lifetime in the sub-nanosecond range. We demonstrate that these defects are spin-active even at room temperature, exhibiting optically detected magnetic resonances (ODMR) in the sub-GHz frequency range. Using ODMR spectroscopy and Ramsey interferometry, we resolve the hyperfine structure arising from the interaction with $^{35}\mathrm{Cl}$ nuclear spins. The ODMR spectra exhibit complex behaviour in an external magnetic field due to mixing of electron-nuclear spin states, which is well reproduced by our simulations. The spin relaxation and coherence times are in the sub-microsecond range, limited by rapid quenching of the ODMR contrast and attributed to charge-state metastability. The combination of telecom-band emission, coherent spin control and compatibility with wafer-scale fabrication positions Cl-related defects in SiC as a promising platform for chip-scale quantum memories with spin-photon interfaces operating in the fiber-optic telecommunication windows.

quant-pharXiv:2605.03717•May 6, 2026•0 citations

Quantum communication networks with defects in silicon carbide

Philipp Sohr, Koller, Philipp, Ecker, Sebastian +23 more

Quantum communication promises unprecedented capabilities enabled by the transmission of quantum states of light. However, current implementations face severe distance limitations due to photon loss. Silicon carbide (SiC) defects have emerged as a promising quantum device platform, offering strong optical transitions, long spin coherence lifetimes and the opportunity for integration with semiconductor devices. Some defects with optical transitions in the telecom range have been identified, allowing to interface with fiber networks without the need for wavelength conversion. These unique properties make SiC an attractive platform for the implementation of quantum nodes for quantum communication networks. We provide an overview of the most prominent defects in SiC and their implementation in spin-photon interfaces. Furthermore, we model an exemplary, memory-enhanced quantum communication protocol in order to extract the parameters required to surpass a direct point-to-point link performance. Based on these insights, we summarize the key steps required towards the deployment of SiC devices in large-scale quantum communication networks.

arXiv:2403.03284•Mar 5, 2024•6 citations
Light emission stemming from V impurities in 4H4H4H-SiC is recorded at 1.28 and 1.33 \ensuremathμ\ensuremath{\mu}\ensuremathμm, in the telecommunication OOO band, which gives hope for the creation of efficient single-photon sources in existing telecommunication networks, ultimately paving the way for secure long-range quantum communication networks. Combined with the available electronic and nuclear degrees of freedom, vanadium presents all of the required ingredients for a highly efficient spin-photon interface. These V centers are reminiscent of the Mo defect in SiC and the Si-VVV complex in diamond, but work at practical wavelengths for telecommunication.
Vanadium color centers in silicon carbide (SiC) offer telecom O-band emission, sub-microsecond optical lifetimes, and second-scale spin relaxation times, rendering them promising candidates for quantum network nodes. However, efficient photon extraction from the high-refractive-index SiC host remains challenging. Here, we introduce a silicon-on-SiC heterogeneous photonic platform in which silicon nanocavities evanescently couple to shallow vanadium dopants in commercial 4H-SiC, enabling efficient zero-phonon line (ZPL) collection under resonant excitation. In as-grown ensembles, we observe Purcell-enhanced photoluminescence with transient spectral hole burning linewidths of 50 MHz on microsecond timescales. In dilute implanted samples, we isolate individual vanadium centers with high-purity single photon emission and a Purcell-enhanced lifetime of 109 ns. The entire optical interface operates through a single lensed fiber, including a 905 nm repump laser that recovers the vanadium charge state with 95% efficiency. These results establish Si-on-SiC as a scalable, foundry-compatible platform for telecom-wavelength spin-photon interfaces.
The conversion between stationary and flying qubits is a pillar of numerous quantum technologies such as distributed quantum computing as well as many quantum internet and networking protocols. These quantum technologies promise to use resources, in particular entanglement, not available to classical devices to accomplish tasks that are difficult or even impossible to realize with classical devices. Applications range from fundamental research to secure communication. Because some of these applications require the generation of entanglement, even over large distances, there is substantial interest in efficient interfaces between flying qubits, usually photons, and a stationary memory. In this thesis, we evaluate key aspects of optical spin-photon interfaces, a class of devices combining a stationary qubit memory (spins) and an interface with flying qubits (photons). We focus on defects in silicon carbide (SiC) in which a transition metal (TM) atom substitutes a silicon (Si) atom in the lattice, so that the energy levels with naturally bound quantum states localized around the defect lie within the band gap of SiC. We highlight two key properties of these defects as stationary-flying interconnects: First, they have favorable spin coherence properties and the pertaining nuclear spin of the TM can be used as a quantum memory. Second, they feature a localized and efficient spin-photon interface via their excited states. Defects where vanadium takes the place of a Si atom even allow for photon emission with frequencies in one of the fiber-optic transmission windows, which support efficient transmission in optical fiber. Our results are readily combined with numerical ab-initio and experimental data, providing intuition and further insight into the underlying physics. Additionally, the theoretical assessments of this thesis bridge the gap between the fundamental characterization of TM defects in SiC and their use as spin-photon interfaces in future experiments and quantum technology applications. For instance, the proposed nuclear-spin preparation protocol and spin control mark the first step towards an all-optically controlled integrated platform for quantum technology with TM defects in SiC.
Spin defects embedded in a scalable material platform with bright telecom emission are promising candidates for quantum communication technologies. V4+{V}^{4+}V4+ in SiC fulfills these criteria, but its potential is limited by the lack of understanding of its spin relaxation mechanisms. This study employs all-optical measurements to reveal that the site-dependent spin T1{T}_{1}T1​ values can exceed 20 seconds and identifies the mechanism of the spin relaxation processes. These insights lead to a proposal to enable qubit operations at higher temperatures, significantly reducing the infrastructure requirements and paving the way for practical realization of quantum technologies based on V4+{V}^{4+}V4+ in SiC.
Quantum networks based on solid-state spin defects present a transformative approach to secure communication and distributed quantum computing, utilizing quantum entanglement and coherent spin–photon interfaces. Silicon carbide (SiC) stands out as a compelling material platform due to its unique combination of a wide bandgap, high optical nonlinearity, CMOS-compatible fabrication, and controllable spin-active defects. These intrinsic properties facilitate efficient photon emission, robust spin coherence at both room and cryogenic temperatures, and integration with photonic nanostructures. Recent advancements in defect engineering and micro-nanophotonics have unlocked the potential of SiC quantum nodes, which feature electron-nuclear spin systems for high-fidelity quantum operations and long-lived quantum memories. Key steps such as single-shot readout and spin-photon entanglement have been successfully demonstrated, bringing SiC closer to a real quantum network platform. This review offers a comprehensive overview of the advancements in SiC-based quantum networks, encompassing key aspects such as defect fabrication methodologies, optimization of spin-photon interfaces, and strategies for photonic integration. Additionally, it examines the existing challenges and outlines promising future directions in this rapidly evolving field.
Realization of quantum memory with a photonic interface in the telecommunication bands in a wafer-scalable platform is a central requirement for long-distance quantum networks. Silicon carbide (SiC) provides a technologically mature host for integrated quantum photonics, yet only a limited number of defects combine spin functionality with telecom emission. Here we report on chlorine-based defects in 4H-SiC as a platform for telecom-band quantum memory. The emission of these defects spans the entire telecommunication range with zero-phonon lines in the O- and C-bands and a Debye-Waller factor of up to 39 %39 \, \%39%. Time-resolved photoluminescence measurements reveal a short excited-state lifetime in the sub-nanosecond range. We demonstrate that these defects are spin-active even at room temperature, exhibiting optically detected magnetic resonances (ODMR) in the sub-GHz frequency range. Using ODMR spectroscopy and Ramsey interferometry, we resolve the hyperfine structure arising from the interaction with 35Cl^{35}\mathrm{Cl}35Cl nuclear spins. The ODMR spectra exhibit complex behaviour in an external magnetic field due to mixing of electron-nuclear spin states, which is well reproduced by our simulations. The spin relaxation and coherence times are in the sub-microsecond range, limited by rapid quenching of the ODMR contrast and attributed to charge-state metastability. The combination of telecom-band emission, coherent spin control and compatibility with wafer-scale fabrication positions Cl-related defects in SiC as a promising platform for chip-scale quantum memories with spin-photon interfaces operating in the fiber-optic telecommunication windows.
Quantum communication promises unprecedented capabilities enabled by the transmission of quantum states of light. However, current implementations face severe distance limitations due to photon loss. Silicon carbide (SiC) defects have emerged as a promising quantum device platform, offering strong optical transitions, long spin coherence lifetimes and the opportunity for integration with semiconductor devices. Some defects with optical transitions in the telecom range have been identified, allowing to interface with fiber networks without the need for wavelength conversion. These unique properties make SiC an attractive platform for the implementation of quantum nodes for quantum communication networks. We provide an overview of the most prominent defects in SiC and their implementation in spin-photon interfaces. Furthermore, we model an exemplary, memory-enhanced quantum communication protocol in order to extract the parameters required to surpass a direct point-to-point link performance. Based on these insights, we summarize the key steps required towards the deployment of SiC devices in large-scale quantum communication networks.