Nanoscale NMR Spectroscopy and Imaging of Multiple Nuclear Species

TL;DR

This paper demonstrates nanoscale NMR spectroscopy and imaging of multiple nuclear species using nitrogen-vacancy centers in diamond, achieving high spatial resolution under ambient conditions, enabling applications in biological and material sciences.

Contribution

It introduces methods for nanoscale NMR and MRI with multiple nuclear species using NV centers, including single NV and high-density NV layers, under ambient conditions.

Findings

Nanoscale NMR spectroscopy of $^1$H and $^{19}$F nuclei on nanometer samples.

Wide-field optical NMR of multiple nuclei with sub-micron resolution.

Identification of surface adsorbed hydrocarbons or water via $^1$H signals.

Abstract

Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) are well-established techniques that provide valuable information in a diverse set of disciplines but are currently limited to macroscopic sample volumes. Here we demonstrate nanoscale NMR spectroscopy and imaging under ambient conditions of samples containing multiple nuclear species, using nitrogen-vacancy (NV) colour centres in diamond as sensors. With single, shallow NV centres in a diamond chip and samples placed on the diamond surface, we perform NMR spectroscopy and one-dimensional MRI on few-nanometre-sized samples containing $^1$H and $^{19}$F nuclei. Alternatively, we employ a high-density NV layer near the surface of a diamond chip to demonstrate wide-field optical NMR spectroscopy of nanoscale samples containing $^1$H, $^{19}$F, and $^{31}$P nuclei, as well as multi-species two-dimensional optical MRI with sub-micron resolution. For all diamond samples exposed to air, we identify a ubiquitous $^1$H NMR signal, consistent with a $\sim 1$ nm layer of adsorbed hydrocarbons or water on the diamond surface and below any sample placed on the diamond. This work lays the foundation for nanoscale NMR and MRI applications such as studies of single proteins and functional biological imaging with subcellular resolution, as well as characterization of thin films with sub-nanometre resolution.