Laser-induced creation of coherent V2 centers in bulk-grown silicon carbide

TL;DR

This paper demonstrates a laser-based method to create coherent V2 spin defects in bulk-grown silicon carbide nanostructures, achieving high yield and preserving optical and spin properties suitable for quantum networks.

Contribution

It introduces a novel laser-induced technique for in-situ creation of V2 centers in silicon carbide nanostructures, enabling scalable defect fabrication for quantum photonics.

Findings

Eleven-fold increase in V2 center occurrence after UV laser illumination.

V2 centers exhibit narrow optical linewidths and spectral diffusion rates similar to natural centers.

Measured spin coherence time of approximately 3.6 ms under dynamical decoupling.

Abstract

Solid-state spin defects are promising qubits for quantum network nodes. A key challenge towards larger networks is creating defects with high yield into nanophotonic devices, while maintaining good optical and spin properties. Here, we demonstrate the creation of V2 centers in nanopillars fabricated from commercial bulk-grown 4H-silicon carbide using a pulsed above-bandgap (UV) laser. We observe an eleven-fold increase in the V2 center occurrence after UV laser illumination. These laser-induced V2 centers exhibit narrow optical linewidths and spectral diffusion rates comparable to naturally occurring V2 centers in nanopillars of the same material. Furthermore, we measure a spin coherence time of $T_{2}^{\mathrm{DD}} = 3.6 \pm 0.3~\text{ms}$ under dynamical decoupling, consistent with dephasing by the nuclear-spin bath. This demonstration of the in-situ, post-fabrication generation of coherent V2 centers in nanostructures in widely available bulk-grown 4H-SiC, shows the potential for above-bandgap laser illumination for scalable defect creation in integrated photonic devices.