Imaging mesoscopic nuclear spin noise with a diamond magnetometer

TL;DR

This paper explores using diamond-based nitrogen-vacancy centers as highly sensitive magnetic sensors for nanoscale nuclear spin imaging, potentially enabling submicrometer MRI of biological samples.

Contribution

It introduces detection protocols that leverage the quantum properties of diamond sensors for high-resolution nuclear spin imaging and spectroscopy.

Findings

Signal-to-noise ratio achievable with realistic parameters

Ability to reconstruct local sample spectra

Potential for high-resolution, submicrometer MRI

Abstract

Magnetic Resonance Imaging (MRI) can characterize and discriminate among tissues using their diverse physical and biochemical properties. Unfortunately, submicrometer screening of biological specimens is presently not possible, mainly due to lack of detection sensitivity. Here we analyze the use of a nitrogen-vacancy center in diamond as a magnetic sensor for nanoscale nuclear spin imaging and spectroscopy. We examine the ability of such a sensor to probe the fluctuations of the "classical" dipolar field due to a large number of neighboring nuclear spins in a densely protonated sample. We identify detection protocols that appropriately take into account the quantum character of the sensor and find a signal-to-noise ratio compatible with realistic experimental parameters. Through various example calculations we illustrate different kinds of image contrast. In particular, we show how to exploit the comparatively long nuclear spin correlation times to reconstruct a local, high-resolution sample spectrum.