Detection and control of single proton spins in a thin layer of diamond grown by chemical vapor deposition

We report detection and coherent control of a single proton nuclear spin using an electronic spin of the nitrogen-vacancy (NV) center in diamond as a quantum sensor. In addition to determining the NV–proton hyperfine parameters by employing multipulse sequences, we polarize and coherently rotate the single proton spin and detect an induced free precession. Observation of free induction decays is an essential ingredient for high resolution proton nuclear magnetic resonance, and the present work extends it to the atomic scale. We also discuss the origin of the proton as incorporation during chemical vapor deposition growth, which provides an opportunity to use protons in diamond as built-in quantum memories coupled with the NV center.