Quantifying NV-center Spectral Diffusion by Symmetry

Solid-state defects are a leading platform for quantum networking owing to their spectrally narrow, spin-dependent optical transitions. A central challenge for scalability of defect-based networking schemes is spectral diffusion of the optical transitions, which limits the entanglement generation rate. In this presentation I will discuss our recent study of several nitrogen-vacancy (NV) centers in bulk diamond. We quantify the photoinduced spectral diffusion caused by the interaction of a charge-state initialization laser with the local electromagnetic environment, as well as the static strain and depth of each defect. To learn more about the origin of the fluctuations, we decompose the spectral diffusion and static strain into components corresponding to Jahn-Teller symmetries of the NV center. We then compute correlations between the various components of spectral diffusion, strain, and depth and look for underlying physics. Our analysis uncovers three key results. First, both spectral diffusion and strain are dominated by perturbations along the NV center's symmetry axis. Second, off-axis strain can protect from some components of off-axis spectral diffusion. Third, optical aberrations with increasing depth can lead to increased spectral diffusion. Our symmetry-decomposed technique for quantifying spectral diffusion can be applied to other solid-state defects of interest and can aid in understanding, and ultimately mitigating, sources of spectral diffusion.