Independent multichannel wavefront modulation for angle and polarization multiplexing through planar metasurfaces

The rapidly growing demand for miniaturized multifunctional devices and systems constantly brings new structural challenges to the research community. The planar metamaterials (metasurfaces) provide a revolutionary way for wavefront manipulation of electromagnetic waves and promise the achievement of superior degrees of freedom. Compared to conventional refractive optical elements, a distinct advantage of metasurfaces can be accomplished by embedding multifunctionality through encoding various sets of information into a single metasurface. Herein, we proposed a unique angle multiplexing strategy that provides wavefront modulation independently in a flat metasurface by controlling the incidence angle of the input light. The fundamental unit cell of the meta-platform of the proposed structure includes a rectangular tetrad with distinct structural geometry. Due to the proposed geometry's geometrical characteristics, the angle multiplexed phenomena are induced in the structure by the mutual coupling of tetrads made of hydrogenated amorphous silicon (a-Si:H). For the proposed metasurface, we exploited the meta-platform comprised of two Meta-atoms, one for positive incidence angle and another for negative incidence angle of light. To increase the applicability of the metasurface, we proposed a single multifunctional meta-device that will project the image of one information for one angle while another information for the opposite angle of the input light. The angle multiplexing phenomena designed for a wavelength can open promising avenues for real-time applications in switchable multifunctional devices, holography, information encryption, and security purposes.