| 1. |
- Babin, Charles, et al.
(författare)
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Fabrication and nanophotonic waveguide integration of silicon carbide colour centres with preserved spin-optical coherence
- 2022
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Ingår i: Nature Materials. - : NATURE PORTFOLIO. - 1476-1122 .- 1476-4660. ; 21, s. 67-73
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Tidskriftsartikel (refereegranskat)abstract
- Colour centres are a promising quantum information platform, but coherence degradation after integration in nanostructures has hindered scalability. Here, the authors show that waveguide-integrated V-Si centres in SiC maintain spin-optical coherences, enabling nuclear high-fidelity spin qubit operations. Optically addressable spin defects in silicon carbide (SiC) are an emerging platform for quantum information processing compatible with nanofabrication processes and device control used by the semiconductor industry. System scalability towards large-scale quantum networks demands integration into nanophotonic structures with efficient spin-photon interfaces. However, degradation of the spin-optical coherence after integration in nanophotonic structures has hindered the potential of most colour centre platforms. Here, we demonstrate the implantation of silicon vacancy centres (V-Si) in SiC without deterioration of their intrinsic spin-optical properties. In particular, we show nearly lifetime-limited photon emission and high spin-coherence times for single defects implanted in bulk as well as in nanophotonic waveguides created by reactive ion etching. Furthermore, we take advantage of the high spin-optical coherences of V-Si centres in waveguides to demonstrate controlled operations on nearby nuclear spin qubits, which is a crucial step towards fault-tolerant quantum information distribution based on cavity quantum electrodynamics.
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| 2. |
- Hesselmeier, Erik, et al.
(författare)
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Qudit-Based Spectroscopy for Measurement and Control of Nuclear-Spin Qubits in Silicon Carbide
- 2024
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 132:9
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Tidskriftsartikel (refereegranskat)abstract
- Nuclear spins with hyperfine coupling to single electron spins are highly valuable quantum bits. Here we probe and characterize the particularly rich nuclear-spin environment around single silicon vacancy color centers (V2) in 4H-SiC. By using the electron spin-3/2 qudit as a four level sensor, we identify several sets of Si29 and C13 nuclear spins through their hyperfine interaction. We extract the major components of their hyperfine coupling via optical detected nuclear magnetic resonance, and assign them to shells in the crystal via the density function theory simulations. We utilize the ground-state level anticrossing of the electron spin for dynamic nuclear polarization and achieve a nuclear-spin polarization of up to 98±6%. We show that this scheme can be used to detect the nuclear magnetic resonance signal of individual spins and demonstrate their coherent control. Our work provides a detailed set of parameters and first steps for future use of SiC as a multiqubit memory and quantum computing platform.
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| 3. |
- Morioka, Naoya, et al.
(författare)
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Spin-controlled generation of indistinguishable and distinguishable photons from silicon vacancy centres in silicon carbide
- 2020
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Quantum systems combining indistinguishable photon generation and spin-based quantum information processing are essential for remote quantum applications and networking. However, identification of suitable systems in scalable platforms remains a challenge. Here, we investigate the silicon vacancy centre in silicon carbide and demonstrate controlled emission of indistinguishable and distinguishable photons via coherent spin manipulation. Using strong off-resonant excitation and collecting zero-phonon line photons, we show a two-photon interference contrast close to 90% in Hong-Ou-Mandel type experiments. Further, we exploit the systems intimate spin-photon relation to spin-control the colour and indistinguishability of consecutively emitted photons. Our results provide a deep insight into the systems spin-phonon-photon physics and underline the potential of the industrially compatible silicon carbide platform for measurement-based entanglement distribution and photonic cluster state generation. Additional coupling to quantum registers based on individual nuclear spins would further allow for high-level network-relevant quantum information processing, such as error correction and entanglement purification. Defects in silicon carbide can act as single photon sources that also have the benefit of a host material that is already used in electronic devices. Here the authors demonstrate that they can control the distinguishability of the emitted photons by changing the defect spin state.
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| 4. |
- Nagy, Roland, et al.
(författare)
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Narrow inhomogeneous distribution of spin-active emitters in silicon carbide
- 2021
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Ingår i: Applied Physics Letters. - : AMER INST PHYSICS. - 0003-6951 .- 1077-3118. ; 118:14
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Tidskriftsartikel (refereegranskat)abstract
- Optically active solid-state spin registers have demonstrated their unique potential in quantum computing, communication, and sensing. Realizing scalability and increasing application complexity require entangling multiple individual systems, e.g., via photon interference in an optical network. However, most solid-state emitters show relatively broad spectral distributions, which hinders optical interference experiments. Here, we demonstrate that silicon vacancy centers in semiconductor silicon carbide (SiC) provide a remarkably small natural distribution of their optical absorption/emission lines despite an elevated defect concentration of approximate to 0.43 mu m - 3. In particular, without any external tuning mechanism, we show that only 13 defects have to be investigated until at least two optical lines overlap within the lifetime-limited linewidth. Moreover, we identify emitters with overlapping emission profiles within diffraction-limited excitation spots, for which we introduce simplified schemes for the generation of computationally relevant Greenberger-Horne-Zeilinger and cluster states. Our results underline the potential of the CMOS-compatible SiC platform toward realizing networked quantum technology applications.
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