Angular Dispersions in Terahertz Metasurfaces: Physics and Applications

Angular dispersion is an intrinsic property of metasurfaces, but its physical origin remains obscure, hindering metasurface design. This work establishes a theory to quantitatively describe such intriguing effects, and verifies it for a typical terahertz metasurface by means of experiments and numerical simulations. With this understanding, the authors propose a design strategy for meta-devices exhibiting incidence-angle-dependent multifunctionalities. As an illustration, they describe a polarization-control device that can behave as a half- or quarter-wave plate under different excitation angles.