Quantum sensing of low-frequency magnetic fields using nitrogen-vacancy (NV) center ensembles has been demonstrated in multiple experiments with sensitivities as low as ∼1 pT/Hz. To date, however, demonstrations of high-frequency magnetometry in the GHz regime with NV diamond are orders of magnitude less sensitive, above the nT/Hz level. Here we adapt for microwave frequencies techniques that have enabled high-performance, low-frequency quantum sensors. Using a custom-grown NV-enriched diamond combined with a noise cancellation scheme designed for high-frequency sensing, we demonstrate a Rabi-sequence-based magnetometer able to detect microwave fields near 2.87 GHz with a record sensitivity of 3.4 pT/Hz. We demonstrate both amplitude and phase sensing and project tunability over a 300 MHz frequency range. This result increases the viability of NV ensembles to serve as microwave circuitry imagers and near-field probes of antennas.
@article{arxiv.2206.15440,
title = {A Solid-State Microwave Magnetometer with Picotesla-Level Sensitivity},
author = {Scott T. Alsid and Jennifer M. Schloss and Matthew H. Steinecker and John F. Barry and Andrew C. Maccabe and Guoqing Wang and Paola Cappellaro and Danielle A. Braje},
journal= {arXiv preprint arXiv:2206.15440},
year = {2022}
}