High Efficiency Flexible Control of Wave Beams Based on Addition and Subtraction Operations on All Dielectric Reflection Metasurfaces

Abstract

In order to reduce the ohmic loss, we propose all dielectric reflection metasurface in terahertz band. The unit structure can be encoded to construct all dielectric reflection encoding metasurfaces. The all dielectric coded metasurfaces consist of the physical coded particles with the coded digits. Since it is impossible for us to design and prepare coded particles of infinitely small size, the traditional coded metasurfaces only control the limited scattering beam directions especially for small deflection angles, and cannot achieve continuous control of scattering angles. This severely limits the wide application of coded metasurfaces. In order to achieve multi-directions and large angle scattering, we introduce the Fourier convolution principle from digital signal processing on all dielectric reflection encoding metasurfaces. Through the addition and subtraction operations of all dielectric encoding metasurface sequences, the freely manipulation of scattering beams can be achieved, especially for larger deflection angles. More importantly, compared with the traditional gradient phase coded metasurfaces, the mixed coded metasurfaces by addition and subtraction operations of encoding sequences can greatly improve the scattering cross section.