Direction control of electromagnetic beam scattering by physically stacked cascaded coding metasurfaces

Abstract

Coded metasurfaces build a bridge between the physical world and digital worlds, making it possible to manipulate electromagnetic waves and implement programmable metamaterials through digitally coded sequences. This “digital metasurface” based on binary digital logic greatly simplifies the design process of the metasurface and improves the flexibility of regulating electromagnetic waves. Based on the principle of Fourier convolution addition, a physical superposition cascaded metasurface is designed. The metasurface unit consists of three dielectric substrates and four “H”-shaped copper metal patch boards. The addition of most coding metasurfaces is to add two basic coding metasurfaces through the addition rules between digital codes to obtain a new coding sequence, and the new coding sequence has the characteristics of the previous two coding sequences. We propose a physically superimposed cascaded encoding metasurface. By physically superposing two different sequences of metasurfaces, the cascaded metasurface formed after superposition also has the characteristics of the first two basic coding sequences. We experimentally verified the proposed idea using two different dielectric materials, and there was good consistency between the experiment and simulation, thereby verifying the consistency of the metasurface cascade and the phase-encoding element surface addition principle. This design approach has potential applications in multifunctional photonic devices.