Optical and Chemical Control of Diamond Interfaces for Quantum Sensing

Spin defects in wide-bandgap semiconductors, such as color centers in diamond, can be highly sensitive to local (nanoscale) changes in magnetic field, temperature, and strain. These solid-state quantum sensors have certain advantages over their atomic counterparts owing to their room-temperature operation without the need for vacuum components and the relative ease of photonic- and RF-component integration. However, near-surface quantum defects exhibit spin decoherence and most of the light emitted is trapped within the bulk crystal due total internal reflection at the interface. I will summarize our work towards better understanding and addressing these interface challenges, including the modeling and characterization of radiative emission of near-surface emitters, design and demonstration of nanoscale light extractors, and surface analysis and chemical termination techniques aimed at improving spin coherence of emitters.