Coherent Control of Nanoscale Nuclear Spin Ensembles in the Spin Noise Regime

TL;DR

This paper explores how the phase and orientation of RF fields influence nuclear spin control in NV centers, revealing critical factors for accurate nanoscale NMR and advancing multidimensional spin resonance techniques.

Contribution

It demonstrates, both theoretically and experimentally, the dependence of nuclear spin dynamics on RF phase and orientation, highlighting an underappreciated aspect of spin manipulation in the spin-noise regime.

Findings

RF phase and orientation critically affect nuclear spin contrast.

Imperfect calibration can cause ambiguous signals.

Results enable more reliable multidimensional spin resonance.

Abstract

Spin defects in solids, such as the nitrogen-vacancy (NV) center in diamond, have emerged as a key tool for detecting nuclear spins at the nanoscale. While active nuclear spin control via radio-frequency (RF) irradiation is often unnecessary for standard spin-noise detection, it becomes essential for advanced protocols like multidimensional nanoscale NMR. In this work, we investigate nuclear spin control using correlation spectroscopy techniques. We demonstrate, both theoretically and experimentally, that the resulting nuclear spin dynamics depend critically on the initial RF phase and its orientation relative to the NV crystalline axis. Depending on these parameters, identical nuclear rotations can yield full, partial, or even vanishing contrast in the NV readout. These findings highlight a previously underappreciated aspect of spin manipulation in the spin-noise regime: the link between the phase and direction of the applied RF field and its direct impact on correlation-based experiments. Consequently, imperfect calibration of these parameters can lead to ambiguous signal contrasts and misinterpretation of the underlying nuclear spin dynamics. Our results provide deeper insight into nanoscale spin control and pave the way toward reliable multidimensional spin resonance experiments.