Three-dimensional magnetic resonance tomography with sub-10 nanometer resolution

We demonstrate three-dimensional magnetic resonance tomography with a resolution down to 5.99 +- 0.07 nm. Our measurements use lithographically fabricated microwires as a source of three-dimensional magnetic field gradients, which we use to image NV centers in a densely doped diamond by Fourier-accelerated magnetic resonance tomography. We also present a compressed sensing scheme for imaging of a spatially localized ensemble from undersampled data, which allows for a direct visual interpretation without numerical optimization. The resolution achieved in our work approaches the positioning accuracy of site-directed spin labeling, paving the way to three-dimensional structure analysis by magnetic-gradient based tomography.