High-coherence integrated nanophotonic multi-spin-photon interface based on silicon vacancies in silicon carbide

Optically active solid-state spins showed multi-node quantum networks, quantum error correction and entanglement distillation.

To claim system scalability, the field has yet to improve the interaction between color centers and photons. While cavity-enhanced light-matter interaction was implemented on multiple platforms, the major challenge is to preserve spin-optical coherence and, simultaneously, grant high-fidelity access to qubit clusters, such as nuclear spins.

Here, we highlight that color centers in semiconductor silicon carbide (SiC) are a promising platform to solve these challenges.

 

We introduce nanofabrication of silicon vacancy centers (V_Si) in 4H-SiC without deterioration of their excellent spin-optical properties. We show nearly lifetime limited optical absorption lines and record spin coherence times for single defects generated via ion implantation and in SiC waveguides.

Thanks to our system’s exceptionally high operation temperature (T = 20 K), we further use waveguide-integrated V_Si centers to control two nearby nuclear spin qubits with fidelities up to 98%. 

Our work shows that V_Si centers in SiC are very attractive for developing next-generation large-scale quantum networks based on integrated quantum computational clusters with efficient spin-photon interfaces.