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dc Quantum Magnetometry below the Ramsey Limit

MetadataDetails
Publication Date2022-11-07
JournalPhysical Review Applied
AuthorsA. A. Wood, Alastair Stacey, A. Martin
InstitutionsThe University of Melbourne, RMIT University
Citations10

We demonstrate quantum sensing of dc magnetic fields that exceeds the sensitivity of conventional ${T}{2}^{\ensuremath{\ast}}$-limited dc magnetometry by more than an order of magnitude. We use nitrogen-vacancy centers in a diamond rotating at periods comparable to the spin coherence time, and characterize the dependence of magnetic sensitivity on measurement time and rotation speed. Our method up-converts only the dc field of interest and preserves the quantum coherence of the sensor. These results definitively improve the sensitivity of a quantum magnetometer to dc fields, demonstrating that sensitivity below the ${T}{2}^{\ensuremath{\ast}}$ limit is possible and can be applied to any diamond magnetometer where ${T}{2}\ensuremath{\gg}{T}{2}^{\ensuremath{\ast}}$ to yield an order-of-magnitude sensitivity improvement.