A Double-Slot Structure as the metasurface geometric phase generating atom for beam controlling

In this paper, a Double-Slot Structure is employed as an atom of metasurfaces for generation of the geometric phase variation on the surface plane. This atom is used for constructing super cells for generating the extraordinary reflection and transmission beams. The numerical results demonstrate that this kind of metasurface can generate the extraordinary reflection and refraction beams up to 54.1 degrees. Note that the structure contains only metal in free space. If loaded with a dielectric substrate, it is expected to further reduce the size of the resonant atom, and hence further increase the extraordinary reflection angle and transmission angles. Because this structure is resonating at the working frequency, both the extraordinary reflection and refraction are significant. The structure is very simple, and is also easy to fabricate for use in very high frequency, for instance in Terahertz domain.