Magnetic Induction Imaging with a cold-atom radio-frequency magnetometer

The sensitive detection of either static or radio-frequency $\text{textsc}(rf)$ magnetic fields is essential to many fundamental studies and applications. Here, we demonstrate the operation of a cold-atom-based, $\text{textsc}rf$ magnetometer in performing {1-D and 2-D imaging} of small metallic objects. It is based on a cold ${}^{85}$Rb atomic sample, and operates in an unshielded environment with no active field stabilization. It shows a sensitivity up to $200\mathrm{p}\mathrm{T}\mathrm{/}\sqrt{\mathrm{H}\mathrm{z}}$ in the $5-35\mathrm{k}\mathrm{H}\mathrm{z}$ range bandwidth and can resolve a cut $0.4\mathrm{m}\mathrm{m}$ wide in a $0.8\mathrm{m}\mathrm{m}$ thick metallic foil. The characteristics of our system make it a good candidate for applications in civil and industrial surveillance.