Fiberized diamond-based vector magnetometers

TL;DR

This paper introduces fiberized vector magnetometers based on diamond NV centers with sub-nT/√Hz sensitivity, small size, and high spatial resolution, suitable for magnetic field mapping in various environments.

Contribution

The work develops portable, fiber-coupled diamond NV magnetometers with enhanced sensitivity and spatial resolution, enabling practical vector magnetic field measurements.

Findings

Achieved sub-nT/√Hz sensitivity in fiberized sensors

Demonstrated 3D magnetic field mapping inside a Halbach array

Sensors are compact, robust, and suitable for high-resolution spatial mapping

Abstract

We present two fiberized vector magnetic-field sensors, based on nitrogen-vacancy (NV) centers in diamond. The sensors feature sub-nT/$\sqrt{\textrm{Hz}}$ magnetic sensitivity. We use commercially available components to construct sensors with a small sensor size, high photon collection, and minimal sensor-sample distance. Both sensors are located at the end of optical fibres with the sensor-head freely accessible and robust under movement. These features make them ideal for mapping magnetic fields with high sensitivity and spatial resolution ($\leq$\,mm). As a demonstration we use one of the sensors to map the vector magnetic field inside the bore of a $\geq$ 100\,mT Halbach array. The vector field sensing protocol translates microwave spectroscopy data addressing all diamonds axes and including double quantum transitions to a 3D magnetic field vector.