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

Authors
Ryota Katsumi, Masaki Sekino, and Takashi Yatsui

Abstract
Ensembles of nitrogen-vacancy (NV) centers in diamond allow for the potential realization of sensitive magnetometers by leveraging their excellent spin properties. However, NV-based magnetometers are limited by their experimental magnetic field sensitivity owing to inefficient photon collection. Moreover, they are disadvantageous for reduced spatial resolution and excessive excitation power. To overcome these issues, we propose ultra-sensitive diamond magnetometers based on nanocavities. The device structure can attain high collection efficiencies 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 indicated that the minimum expected sensitivity is 60 fT/√Hz. Proposed design can achieve volume-normalized sensitivity of 0.92 aT/√(Hz/cm³) along with a required power of 7 μW, both of which are superior to those of bulk diamond. The proposed approach offers a promising route toward highly sensitive and energy-efficient magnetometers.

Japanese Journal of Applied Physics (JJAP)：https://iopscience.iop.org/article/10.35848/1347-4065/ac7e10