There has been recent excitement about the performance of defects (such as vacancies, or missing atoms) in crystalline semiconductors, where the defect, also termed qubit, can manifest optical emission at a variety of wavelengths, distinctively coupled to long spin coherence times. The deliberate creation of such defects, for example with ion beam irradiation, almost certainly implies the creation of “collateral” defects and disorder to the surrounding environment: how does this affect luminescence efficiency, spin coherent lifetimes and other important qubit metrics?

This talk will focus on Silicon Vacancies in 4H SiC, integrated into “bespoke” nanoscale optical cavities, with an effective volume of about (100 nm)3. The cavities serve to augment the optical signal by orders of magnitude, but also serve as “nanoscopes” into the material, allowing us to learn about the interactions with surrounding defects, and giving us broader insights into longer-term quantum coherence.