Quantum sensors in diamonds for magnetic resonance spectroscopy: Current applications and future prospects

Nuclear magnetic resonance (NMR) and electron spin resonance (ESR) methods are indispensable techniques that utilize the spin of particles to probe matter, with applications in various disciplines, including fundamental physics, chemistry, biology, and medicine. Despite their versatility, the technique's sensitivity, particularly for NMR, is intrinsically low, which typically limits the detection of magnetic resonance (MR) signals to macroscopic sample volumes. In recent years, atom-sized magnetic field quantum sensors based on nitrogen-vacancy (NV) centers in diamond paved the way to detect MR signals at the micro- and nanoscale, even down to a single spin. In this perspective, we offer an overview of the most promising directions in which this evolving technology is developing. Significant advancements are anticipated in the life sciences, including applications in single molecule and cell studies, lab-on-a-chip analytics, and the detection of radicals or ions. Similarly, NV-MR is expected to have a substantial impact on various areas in the materials research, such as surface science, catalysis, 2D materials, thin films, materials under extreme conditions, and quantum technologies.