Towards magnetic imaging of neurons using NV diamond

Magnetic field imaging based on optically detected magnetic resonances (ODMR) in NV diamond offers an unmatched combination of sensitivity, resolution and field-of-view. For certain biological applications NV diamond imaging is particularly useful; in contrast to traditional fluorescent markers, NV diamond imaging is label-free and does not suffer from bleaching. Additionally the solid-state nature of NV diamond imaging allows for various fast modulation techniques to be employed to increase the signal-to-noise ratio. Here we present progress towards creating an NV diamond imager with sensitivity and resolution appropriate for imaging neural activity within a living neural network. When integrating over our detector, we demonstrate a DC magnetic field sensitivity of better than 50 pT/Hz$^{1/2}$, which we demonstrate is suitable for detecting the action potentials in invertebrate giants axons.