Biocompatible technique for nanoscale magnetic field sensing with Nitrogen-Vacancy centers

The possibility of using Nitrogen-vacancy centers in diamonds to measure nanoscale magnetic fields with unprecedented sensitivity is one of the most significant achievements of quantum sensing. Here we present an innovative experimental set-up, showing an achieved sensitivity comparable to the state of the art ODMR protocols if the sensing volume is taken into account. The apparatus allows magnetic sensing in biological samples such as individual cells, as it is characterized by a small sensing volume and full bio-compatibility. The sensitivity at different optical powers is studied to extend this technique to the intercellular scale.