Nanofabrication of quantum-grade colour centres in silicon carbide

Florian Kaiser
Physikalisches Institut, Universit├Ąt Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany

Solid-state spins with optical interfaces showed multi-node quantum networks, quantum error correction and entanglement distillation.
To boost these systems to field-ready implementations, the field has still to improve the interaction between colour centres 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 colour centres in semiconductor silicon carbide (SiC) are a promising platform to solve these challenges. We introduce nanofabrication of silicon vacancy centres (VSi) 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. This allows us also to control two nearby nuclear spin qubits with fidelities up to 98%.
In the outlook, I will present our additional advances in coupling VSi centres to optical fibres and discuss the need for high-accuracy defect generation via implantation of light ions.