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arXiv · 2112.11612

High-Field Magnetometry with Hyperpolarized Nuclear Spins

Ozgur Sahin·Erica de Leon Sanchez·Sophie Conti·Amala Akkiraju·Paul Reshetikhin·Emanuel Druga·Aakriti Aggarwal·Benjamin Gilbert·Sunil Bhave·Ashok Ajoy
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Abstract

Quantum sensors have attracted broad interest in the quest towards sub-micronscale NMR spectroscopy. Such sensors predominantly operate at low magnetic fields. Instead, however, for high resolution spectroscopy, the high-field regime is naturally advantageous because it allows high absolute chemical shift discrimination. Here we propose and demonstrate a high-field spin magnetometer constructed from an ensemble of hyperpolarized ${}^{13}C$ nuclear spins in diamond. The ${}^{13}C$ nuclei are initialized via Nitrogen Vacancy (NV) centers and protected along a transverse Bloch sphere axis for minute-long periods. When exposed to a time-varying (AC) magnetic field, they undergo secondary precessions that carry an imprint of its frequency and amplitude. The method harnesses long rotating frame ${}^{13}C$ sensor lifetimes $T_2^{\prime}{>}$20s, and their ability to be continuously interrogated. For quantum sensing at 7T and a single crystal sample, we demonstrate spectral resolution better than 100 mHz (corresponding to a frequency precision ${<}$1ppm) and single-shot sensitivity better than 70pT. We discuss the advantages of nuclear spin magnetometers over conventional NV center sensors, including deployability in randomly-oriented diamond particles and in optically scattering media. Since our technique employs densely-packed ${}^{13}C$ nuclei as sensors, it demonstrates a new approach for magnetometry in the "coupled-sensor" limit. This work points to interesting opportunities for microscale NMR chemical sensors constructed from hyperpolarized nanodiamonds and suggests applications of dynamic nuclear polarization (DNP) in quantum sensing.

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Ozgur Sahin, Erica de Leon Sanchez, Sophie Conti, Amala Akkiraju, Paul Reshetikhin, Emanuel Druga, Aakriti Aggarwal, Benjamin Gilbert, Sunil Bhave, Ashok Ajoy. 2021-12-22. High-Field Magnetometry with Hyperpolarized Nuclear Spins. https://doi.org/10.1038/s41467-022-32907-8

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