Determination of the position of a single nuclear spin from free nuclear precessions detected by a solid-state quantum sensor

We report on a nanoscale quantum sensing protocol which tracks a free precession of a single nuclear spin and is capable of estimating an azimuthal angle-a parameter which standard multipulse protocols cannot determine-of the target nucleus. Our protocol combines pulsed dynamic nuclear polarization, a phase-controlled radio-frequency pulse, and a multipulse ac sensing sequence with a modified readout pulse. Using a single nitrogen-vacancy center as a solid-state quantum sensor, we experimentally demonstrate this protocol on a single C-13 nuclear spin in diamond and uniquely determine the lattice site of the target nucleus. Our result paves the way for magnetic resonance imaging at the single-molecular level.