A bell-bloom atomic magnetic-videorecorder with global shutter and differential readout

Weak magnetic video recording with warm atomic ensembles constitutes a non-cryogenic and non-contact methodology for the magnetic source identification and failure reproduction. However, the spatial resolution, imaging speed, and shooting mode from traditional optical-pumping systems have constrained the real recording for ever-changing magnetic phenomena. This work reports a 684-pixel Bell-Bloom atomic magnetic-videorecorder with the global shutter and two-dimensional differential readout, for the real recording of changing gradient fields, which implements the free Larmor precession of Cs atoms to infer local magnetic information, employs a high-speed dual-quadrant Complementary Metal Oxide Semiconductor (CMOS) sensor with the global shutter and the extra microlens focusing to simultaneously detect differential optical rotations on all pixels. Also, a digital micro-mirror device (DMD) is employed to weigh the pixel crosstalk and the spatial resolution, and to facilitate the one-to-one pairing of the profiles for each differential probe beam pair projected onto the two CMOS quadrants. Furthermore, the average sensitivity is demonstrated to be 194 pT/ $\sqrt{\mathrm{Hz}}$ @0.5-178 Hz, with a high spatial resolution of 137 μm² and a frame rate of 205 fps in a field of view up to 5 × 2.6 mm². Finally, the magnetic distributions from a moving source have been experimentally measured and found to be in good agreement with the simulation results.