Keigo Arai

Selective addressing of solid-state spins at the nanoscale via magnetic resonance frequency encoding

The nitrogen vacancy centre in diamond is a leading platform for nanoscale sensing and imaging, as well as quantum information processing in the solid state. To date, individual control of two nitrogen vacancy electronic spins at the nanoscale has been demonstrated. However, a key challenge is to scale up such control to arrays of nitrogen vacancy spins. Here, we apply nanoscale magnetic resonance frequency encoding to realize site-selective addressing and coherent control of a four-site array of nitrogen vacancy spins. Sites in the array are separated by 100 nm, with each site containing multiple nitrogen vacancies separated by ~15 nm. Microcoils fabricated on the diamond chip provide electrically tuneable magnetic field gradients ~0.1 G/nm. Tailored application of gradient fields and resonant microwaves allow site-selective nitrogen vacancy spin manipulation and sensing applications, including Rabi oscillations, imaging, and nuclear magnetic resonance spectroscopy with nanoscale resolution. Microcoil-based magnetic resonance of solid-state spins provides a practical platform for quantum-assisted sensing, quantum information processing, and the study of nanoscale spin networks.Selective nanoscale addressing of solid-state spinsArrays of spins in solids are a promising modality for a wide range of quantum science applications—from sensing to information processing. A team led by Ronald Walsworth at Harvard University adapted methods from magnetic resonance imaging (MRI) to realize site-selective addressing and coherent control of small arrays of optically active electronic spins in diamond known as nitrogen vacancy (NV) colour centres. Microcoils fabricated on the diamond chip provide electrically tunable magnetic field gradients that allow selective NV spin addressing with 30 nm resolution. The team experimentally demonstrated site-selective NV electron spin resonance spectroscopy, Rabi oscillations, Fourier magnetic imaging, and nuclear magnetic resonance (NMR) spectroscopy. The approach should be scalable to selective coherent control of large-scale arrays of strongly interacting NVs, with a broad spectrum of high-impact quantum science applications.