Laser-Induced Creation of Coherent V2 Centers in Bulk-Grown Silicon Carbide.

Abstract

Solid-state spin defects are promising qubits for quantum network nodes. A key challenge toward larger networks is creating defects with high yield into nanophotonic devices while maintaining good optical and spin properties. Here, we demonstrate the creation of single V2 centers in nanopillars fabricated from commercial bulk-grown 4H-silicon carbide using a pulsed above-bandgap (UV) laser. We observe an 11-fold increase in the V2 center occurrence after UV laser illumination. These laser-induced V2 centers exhibit narrow optical line widths and spectral diffusion rates comparable to naturally occurring V2 centers in nanopillars of the same material. Furthermore, we measure a spin coherence time of <math xmlns="http://www.w3.org/1998/Math/MathML"><msubsup><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow><mrow><mi>D</mi><mi>D</mi></mrow></msubsup><mo>=</mo><mn>3.6</mn><mrow><mo>(</mo><mn>3</mn><mo>)</mo></mrow><mspace></mspace><mi>ms</mi></math> under dynamical decoupling, consistent with dephasing by the nuclear-spin bath. This demonstration of the in situ, postfabrication 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.