Optical hyperpolarization of heteronuclear spin singlet order in liquids

TL;DR

This paper demonstrates the first optical hyperpolarization of heteronuclear spin singlet order in liquids, using NV centers in nanodiamonds to achieve long-lived nuclear spin hyperpolarization at room temperature.

Contribution

It introduces a novel method for hyperpolarizing heteronuclear spin singlet order in liquids using optically polarized NV centers, expanding hyperpolarization techniques.

Findings

Hyperpolarized heteronuclear singlet order achieved in $^{13}$C-labeled formic acid.

Room temperature hyperpolarization using NV centers in nanodiamonds.

Long-lived nuclear spin hyperpolarization demonstrated.

Abstract

The nuclear spin singlet order involving coupled pairs of spins-1/2 may be used to store nuclear spin hyperpolarization in a room temperature liquid for a time much longer than the spin-lattice relaxation time $T_1$. There both are observations of long-lived homonuclear and heteronuclear spin-singlet order. Although hyperpolarized singlet order of the same species are accessible, hyperpolarized heteronuclear spin-singlet order has not been presented yet. Here we show hyperpolarized singlet order is achievable in the sample of $^{13}$C-labeled formic acid solution at room temperature by using optically polarized nitrogen vacancy (NV) center spins in nanodiamonds.