Coherent signal detection in the statistical polarization regime enables high-resolution nanoscale NMR spectroscopy

TL;DR

This paper introduces a method for high-resolution nanoscale NMR spectroscopy using NV centers in diamond, overcoming previous limitations by detecting coherent signals from polarized samples, enabling spectral resolution of a few hertz.

Contribution

The authors demonstrate that detecting coherent signals from polarized nanoscale samples enables high-resolution NMR spectroscopy at the nanometer scale, surpassing previous statistical polarization limitations.

Findings

Achieved single-digit hertz spectral resolution in nanoscale NMR.

Enabled resolution of scalar couplings at the nanoscale.

Demonstrated detection of coherent signals from polarized samples.

Abstract

Nitrogen-vacancy (NV) centers in diamond have emerged as quantum sensors capable of detecting nuclear magnetic resonance (NMR) signals at unprecedented length scales, ranging from picoliter sample volumes down to single spins at the diamond surface. While high-resolution (few hertz) NV-NMR spectroscopy has been demonstrated at the micrometer scale, it has remained elusive at the nanometer scale. In this regime, only the detection of statistical polarization has been achieved, limiting spectral resolution due to molecular diffusion in liquid samples. Here, we demonstrate that detecting coherent signals from a uniformly polarized nanoscale sample, where polarization is enhanced beyond thermal levels, successfully overcomes this limitation, enabling single-digit hertz spectral resolution and the capacity to resolve scalar couplings. These results pave the way for high-resolution nanoscale NMR spectroscopy at interfaces, surfaces, and potentially even single molecules.