We present a new method for high-resolution nanoscale magnetic resonance
imaging (nano-MRI) that combines the high spin sensitivity of nanowire-based
magnetic resonance detection with high spectral resolution nuclear magnetic
resonance (NMR) spectroscopy. By applying NMR pulses designed using optimal
control theory, we demonstrate a factor of 500 reduction of the proton spin
resonance linewidth in a (50-nm)3 volume of polystyrene and
image proton spins in one dimension with a spatial resolution below
2nm.Comment: Main text: 8 pages, 6 figures; supplementary information: 10 pages,
10 figure