Solid-State Microwave Magnetometer with Picotesla-Level Sensitivity

Abstract

Magnetometry with diamond nitrogen-vacancy (NV) ensembles has enabled devices with picotesla sensitivity at static and low-frequency fields, but their performance at higher frequencies lags far behind. The authors solve the technical challenges and demonstrate a microwave-frequency NV magnetometer with picotesla sensitivity, by implementing a pulse scheme for noise cancellation and employing a custom-grown diamond. This sensitivity enhancement could be extended into a far broader range of frequencies using spin-locking and quantum frequency mixing. These results could lead to applications such as near-field antenna characterization and microwave circuitry imaging.