Quantum magnetic resonance microscopy

TL;DR

This paper introduces a quantum magnetic resonance microscope using nitrogen-vacancy centers in diamond, achieving high-resolution electron spin imaging at nanoscopic scales with unprecedented sensitivity, enabling new applications in chemistry and biology.

Contribution

It demonstrates a novel quantum control-based magnetic resonance imaging technique with diffraction-limited resolution and zeptomole sensitivity, surpassing traditional limitations.

Findings

Achieved diffraction-limited spatial resolution of ~50x50 μm^2.

Detected as few as 10^4 spins per voxel with zeptomole sensitivity.

Enabled imaging and spectroscopy of aqueous Cu2+ ions at nanoscopic volumes.

Abstract

Magnetic resonance spectroscopy is universally regarded as one of the most important tools in chemical and bio-medical research. However, sensitivity limitations typically restrict imaging resolution to length scales greater than 10 \mu m. Here we bring quantum control to the detection of chemical systems to demonstrate high resolution electron spin imaging using the quantum properties of an array of nitrogen-vacancy (NV) centres in diamond. Our quantum magnetic resonance microscope selectively images electronic spin species by precisely tuning a magnetic field to bring the quantum probes into resonance with the external target spins. This provides diffraction limited spatial resolution of the target spin species over a field of view of ~50x50 \mu m^2. We demonstrate imaging and spectroscopy on aqueous Cu2+ ions over microscopic volumes (0.025 \mu m^3), with detection sensitivity at resonance of 104 spins/voxel, ~100 zeptomol (10^-19 mol). The ability to image, perform spectroscopy and dynamically monitor spin-dependent redox reactions and transition metal biochemistry at these scales opens up a new realm of nanoscopic electron spin resonance and zepto-chemistry in the physical and life sciences.