Design of an ultra-sensitive and miniaturized diamond NV magnetometer based on a nanocavity structure

The ensemble of nitrogen-vacancy (NV) centers in diamond allows for the potential realization of the sensitive magnetometers by leveraging their excellent spin properties. However, the NV-based magnetometers are limited by their experimental magnetic field sensitivity owing to its inefficient photon collection. Moreover, they are a disadvantage to the reduced spatial resolution and excessive excitation power. To overcome these issues, we propose a ultra-sensitive diamond magnetometer based on nanocavities. The device structure can attain a high collective efficiency and enhance the photon emission intensity of the NV ensemble. This device can allow the efficient photon collection even when considering the positional distribution of the NV centers. Our theoretical analysis indicates that the minimum expected sensitivity is 60 fT/root Hz. The proposed design can achieve a volume-normalized sensitivity of 0.92 aT/root Hz cm(-3) along with the required power of 7 mu W, both of which are superior to those of bulk diamond. The proposed approach offers a promising route towards highly sensitive and energy-efficient magnetometers. (c) 2022 The Author(s). Published on behalf of The Japan Society of Applied Physics by IOP Publishing Ltd

Automated summary

In this study, a ultra-sensitive diamond magnetometer based on nanocavities is proposed to overcome the limitations of traditional NV-based magnetometers in terms of experimental magnetic field sensitivity, spatial resolution, and excitation power. The device structure enhances the photon emission intensity and collective efficiency of the NV ensemble, enabling efficient photon collection even considering the positional distribution of the NV centers.