Quantum Sensing in Tweezer Arrays: Optical Magnetometry on an Individual-Atom Sensor Grid

Abstract

We implement a scalable platform for quantum sensing comprising hundreds of sites capable of holding individual laser-cooled atoms and demonstrate the applicability of this single-quantum-system sensor array to magnetic field mapping on a two-dimensional grid. With each atom being confined in an optical tweezer within an area of 0.5μm^{2} at mutual separations of 7.0(2)μm, we obtain micrometer-scale spatial resolution and highly parallelized operation. An additional steerable optical tweezer allows rearrangement of atoms within the grid and enables single-atom scanning microscopy with submicron resolution. This individual-atom sensor platform finds an immediate application in mapping an externally applied dc gradient magnetic field. In a Ramsey-type measurement, we obtain a field resolution of 98(29) nT. We estimate the sensitivity to be 25μT/sqrt[Hz].