Talk by Dr. Daniel Higginbottom, Simon Fraser University


Silicon colour centres for quantum technology

Speaker: Dr. Daniel Higginbottom

When:     11.07.2023

Where:   Ernst Mach Lecture Hall (2nd floor, Boltzmanngasse 5)

The performance of modular, networked quantum technologies will be contingent upon the quality of their light-matter interconnects. Solid-state colour centres can offer optically-coupled spin qubit registers as the basis for quantum networks and distributed quantum computing. Of the potential solid-state hosts, silicon is an ideal platform for commercial quantum technologies: it unites advanced photonics and the microelectronics industry, as well as hosting record-setting long-lived spin qubits. However native silicon emitters, silicon colour centres, have been comparatively neglected. One such emitter, the T centre, was recently discovered to combine direct telecommunications-band photonic emission, long-coherence electron and nuclear spins [1,2], and proven integration into industry-standard, CMOS-compatible, silicon-on-insulator (SOI) photonic chips at scale. In this talk I present recent advances fabricating nanophotonic T centre devices, enabling the first all-optical measurement of individual spins in silicon [3]. We determine the homogeneous linewidths of integrated centres and enhance the optical emission rate by an order of magnitude with optical nanocavities to create coherent optical interfaces. We determine the anisotropic ground state spin Hamiltonian and demonstrate how each T centre may be operated as a deterministic four-qubit spin register. T centre devices producing spin-entangled photons can make immediate use of integrated silicon photonic networks boasting low-loss active components, efficient coupling to standard telecommunications fibres, and efficient on-chip photon detectors. These elements may be assembled to create an on-chip spin-photon quantum processor that interfaces with optical fibres for long-range communication over the quantum internet.

[1] L. Bergeron et al., Silicon-integrated telecommunications photon-spin interface, PRX Quantum, 1(2), 20301 (2020).

[2] D. Dhaliah et al., First-principles study of the T center in silicon. Physical Review Materials, 6(5), L053201. (2022)

[3] D. B. Higginbottom et al., Optical observation of single spins in silicon, Nature, 607, 266-270 (2022).