Through-skin pilot-hole detection and localization with a mechanically translatable atomic magnetometer

We demonstrate through-skin electromagnetic induction imaging of pilot-holes in an aluminum block concealed by a 0.41 mm thick shield with 1.49 kg mechanically translatable radio frequency atomic magnetometer. The are identified and localized submillimeter accuracy both without the Al shield. utilize dual-frequency technique to isolate image target while removing effect shielding from image. Imaging is shown be robust range different operating conditions immune thermal insulator between target. approach introduced here finds direct application aircraft wing manufacture competitive existing approaches.