Dual functionality of a single-layer metasurface: polarization rotator and polarizer

Single-layered metasurfaces are easier to fabricate than multi-layered ones but suffering from low efficiency and/or narrow bandwidth for transmissive polarization rotation. In this work, we propose a single-layered metasurface which can realize 90° polarization rotation with high efficiency, wide bandwidth, and ultra-high polarization conversion ratio in transmission mode. In addition, the single-layered metasurface can also be used as an efficient and wideband polarizer, which couples the two orthogonal electric components of incident light to the transmitted polarization.