Compact Optical Rotation Detection for Atomic Magnetometers Enabled by Beam-Splitting Metalens

High-performance atomic magnetometers (AMs) detect magnetic fields via optical rotation measurement, but the bulky balanced polarimeter required for this measurement makes AM miniaturization challenging. To address this issue, we replace traditional optical components such as Wollaston prisms with a single monolithic metalens to achieve integrated detection of magnetically induced optical rotation, thereby dramatically reducing the device s footprint. The designed metalens splits a pair of orthogonal linear polarizations with deflection angles of ±10° and focuses them to two spatially separated focal spots with a simulated focusing efficiency up to 90%. We envisage that this metalens paves the way for chip-scale integration of emerging atomic devices, expanding applications of AMs in critical fields including biomagnetic imaging and paleomagnetism..