Remote chip-scale quantum sensing of magnetic fields

Quantum sensing is an ever-evolving research field describing the use of a quantum phenomenon to perform measurement of a physical quantity. Amongst different types of quantum sensors, atomic vapor-based quantum effects are extensively used to measure quantities such as time, velocity, acceleration, electric, and magnetic fields. Here, we propose and demonstrate remote quantum sensing using a chip-scale atomic vapor cell. Specifically, we remotely interrogate millimeter-scale micromachined vapor cells, and measure the ambient Earth’s magnetic field at a standoff distance of ∼10 m and a sensitivity of ∼1 pT/√Hz. We further spatially map different magnetic fields in the presence of a noisy ambient environment. Simultaneously we are able measure the distance between a micro-cell and the interrogating system by means of time-of-flight measurements, thus correlating between position and magnetic field. Utilizing micromachined vapor cells for remote magnetometry offers substantial advantages in scalability, planar photonic integration, cost, and size. Consequently, we provide a novel toolset to deploy, measure, and map arbitrary, remote, and hard-to-access magnetic fields in unshielded environments with high sensitivity and spatial resolution, paving the way to a variety of novel applications in diverse fields such as medicine, communication, defense, space-exploration, and quantum technologies.