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arXiv · 2309.04093

Diamond quantum magnetometer with dc sensitivity of < 10 pT Hz$^{-1/2}$ toward measurement of biomagnetic field

N. Sekiguchi·M. Fushimi·A. Yoshimura·C. Shinei·M. Miyakawa·T. Taniguchi·T. Teraji·H. Abe·S. Onoda·T. Ohshima·M. Hatano·M. Sekino·T. Iwasaki
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Abstract

We present a sensitive diamond quantum sensor with a magnetic field sensitivity of $9.4 \pm 0.1~\mathrm{pT/\sqrt{Hz}}$ in a near-dc frequency range of 5 to 100~Hz. This sensor is based on the continuous-wave optically detected magnetic resonance of an ensemble of nitrogen-vacancy centers along the [111] direction in a diamond (111) single crystal. The long $T_{2}^{\ast} \sim 2~\mathrm{\mu s}$ in our diamond and the reduced intensity noise in laser-induced fluorescence result in remarkable sensitivity among diamond quantum sensors. Based on an Allan deviation analysis, we demonstrate that a sub-picotesla field of 0.3~pT is detectable by interrogating the magnetic field for a few thousand seconds. The sensor head is compatible with various practical applications and allows a minimum measurement distance of about 1~mm from the sensing region. The proposed sensor facilitates the practical application of diamond quantum sensors.

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N. Sekiguchi, M. Fushimi, A. Yoshimura, C. Shinei, M. Miyakawa, T. Taniguchi, T. Teraji, H. Abe, S. Onoda, T. Ohshima, M. Hatano, M. Sekino, T. Iwasaki. 2023-09-08. Diamond quantum magnetometer with dc sensitivity of < 10 pT Hz$^{-1/2}$ toward measurement of biomagnetic field. https://doi.org/10.1103/physrevapplied.21.064010

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