Polarization-Multiplexed Moiré Metasurfaces for Multifocus Steering and Flexible Polarization Transformation

Traditional optical elements are limited in multidimensional light field manipulation due to their bulkiness and restricted degrees of freedom. While mechanically reconfigurable bilayer Moiré metasurfaces excel in beam steering, they lack the capability for dynamic polarization modulation. Here, we integrate mechanical modulation and polarization multiplexing into a novel rotatable bilayer metasurface with spin-decoupled phase control. Under linearly polarized incidence, the device generates two focal spots, each steerable over a ±20° range with tunable polarizations: one transitions between radial and azimuthal vector states, and the other adjusts linearly from the x to the y axis. This enables synchronous spiral phase contrast imaging and bright-field imaging, advancing dynamic beam control through the integration of focusing, steering, and polarization transformation.