Local, mm-scale $^1$H magnetic resonance imaging using atomic vapors

We demonstrate a practical and sensitive low-field approach to magnetic resonance imaging (MRI) of μL-scale samples using an optically pumped magnetometer (OPM). Using a simple setup where a commercial OPM is placed directly adjacent to a sample, without intermediary signal-pickup coils, we perform one- and two-dimensional imaging with a >1 cm field of view and sub-mm Fourier-limited resolution at 10 μT, near earth's field. This enables (i) high-throughput, low-field MRI of fluidic and tissue samples, and (ii) a quantitative benchmark of the sensitive volume surrounding the OPM.