We present a highly sensitive miniaturized cavity-enhanced room-temperature magnetic-field sensor based on nitrogen-vacancy (NV) centers in diamond. The magnetic resonance signal is detected by probing absorption on the 1042\,nm spin-singlet transition. To improve the absorptive signal the diamond is placed in an optical resonator. The device has a magnetic-field sensitivity of 28 pT/Hz, a projected photon shot-noise-limited sensitivity of 22 pT/Hz and an estimated quantum projection-noise-limited sensitivity of 0.43 pT/Hz with the sensing volume of ∼ 390 μm × 4500 μm2. The presented miniaturized device is the basis for an endoscopic magnetic field sensor for biomedical applications.
@article{arxiv.1706.02201,
title = {Miniature cavity-enhanced diamond magnetometer},
author = {Georgios Chatzidrosos and Arne Wickenbrock and Lykourgos Bougas and Nathan Leefer and Teng Wu and Kasper Jensen and Yannick Dumeige and Dmitry Budker},
journal= {arXiv preprint arXiv:1706.02201},
year = {2017}
}