Optically-probed nitrogen-vacancy (NV) quantum defects in diamond can detect nuclear magnetic resonance (NMR) signals with high-spectral resolution from micron-scale sample volumes of about 10 picoliters. However, a key challenge for NV-NMR is detecting samples at millimolar concentrations. Here, we demonstrate an improvement in NV-NMR proton concentration sensitivity of about 105 over thermal polarization by hyperpolarizing sample proton spins through signal amplification by reversible exchange (SABRE), enabling micron-scale NMR of small molecule sample concentrations as low as 1 millimolar in picoliter volumes. The SABRE-enhanced NV-NMR technique may enable detection and chemical analysis of low concentration molecules and their dynamics in complex micron-scale systems such as single-cells.
@article{arxiv.2006.03910,
title = {Micron-scale SABRE-enhanced NV-NMR Spectroscopy},
author = {Nithya Arunkumar and Dominik B. Bucher and Matthew J. Turner and Patrick TomHon and David Glenn and Soren Lehmkuhl and Mikhail D. Lukin and Hongkun Park and Matthew S. Rosen and Thomas Theis and Ronald L. Walsworth},
journal= {arXiv preprint arXiv:2006.03910},
year = {2021}
}