Polarization-multiplexed Janus coding metasurfaces for versatile and customizable terahertz imaging

Abstract This work presents a scheme for realizing versatile and customizable terahertz imaging using polarization-multiplexed Janus coding Metasurfaces. Building on a reflective meta-atom enabling asymmetric intensity-modulated focal spots and tailorable imaging under linearly polarized (LP) waves incidence, we develop a Janus meta-atom to facilitate the unique asymmetric and reciprocal transmission. As proofs of concept, two Janus coding metasurfaces are constructed to achieve customizable holographic patterns and focal spots, which can produce spatially complementary holographic patterns and position-shifted focus for oppositely incident LP waves. This work demonstrates bidirectional polarization-multiplexing wavefront reconfiguration capabilities, offering promising approaches toward compact and customizable terahertz-integrated devices.