Multifunctional All-Dielectric Metasurfaces

Cascaded dielectric metasurfaces that provide distinct polarization conversion/control at different bands are introduced. A step-by-step design approach is presented to realize a wide range of polarization transformations with metasurfaces employing simple geometries. The proposed metasurfaces consist of cascaded subwavelength gratings with varying orientations that are separated by isotropic spacers. These metasurfaces can be designed to function as broadband or multiband polarization filters, as well as multifunctional polarization converters that are compact (wavelength-scaled) and low-loss.