High-speed, sensitive NV-diamond magnetic imager for microscopic biomagnetism

Diamond-based optical magnetometry using nitrogen-vacancy (NV) defect centers is uniquely positioned to detect micrometer-scale biomagnetic fields, enabling applications in neuroscience, NMR and rare-cell detection. Developing an NV magnetometer with high-speed, sensitive, and wide-field imaging capability is a crucial step towards mapping of dynamic magnetic fields from transient local neuronal activities. Leveraging recent Ramsey-based imaging protocols, which has enhanced sensitivity, bandwidth, and uniformity compared to conventional continuous-wave optically detected magnetic resonance (CW-ODMR) method, we present a high-sensitivity, broadband magnetic imager capable of resolving sub-millisecond-scale temporal magnetic dynamics with improved robustness to experimental imperfections. We characterize the trade-offs among spatial resolution, bandwidth and minimal detectable field, and discuss near-term imaging applications in neuronal and other cellular-level magnetism. We further suggest potential avenues to improve SNR and detect ever smaller magnetic fields.