A Mode-Localized Magnetometer with Resolution of $6.9\ \text{NT}/ \surd \text{Hz}$ Within the Range of 100 mT

This paper reports a mode-localized magnetometer with novel 3 degrees-of-freedom (DOF) weakly coupled resonators (WCRs) coupled by F-shaped coupling beams. In this coupling mechanism, the direct coupling between the two outer resonators can be effectively suppressed, which decreases the coupling coefficient and drastically increases the sensitivity. Utilizing these novel WCRs for Lorentz force sensing, a magnetometer is realized with the resolution of $6.9\ \text{nT}/\surd \text{Hz}$ in the range of 100 mT, which is an improvement of 234.78 times that of state-of-the-art mode-localized magnetometers ( $1.62\ \mu \mathrm{T}/\surd\text{Hz}$ ).