Abstract-Angular dispersions in terahertz metasurfaces: Physics and applications

Meng Qiu, Min Jia, Shaojie Ma, Shulin Sun, Qiong He,  Lei Zhou,

https://journals.aps.org/prapplied/accepted/20070AedD5e1680fa1d60312978c2b8f3fcbaf4b7

Angular dispersion --- the response of a metasurface strongly depends on the impinging angle --- is an intrinsic property of metasurfaces, but its physical origin remains obscure which also hinders its applications in metasurface design. Here, we establish a theory to quantitatively describe such intriguing effects in metasurfaces, and verify it by both experiments and numerical simulations on a typical terahertz metasurface. The physical understanding gained motivates us to propose a new strategy to design meta-devices exhibiting impinging-angle-dependent multi-functionalities. As an illustration, we design a polarization-control meta-device that can behave as a half or quarter wave plate under different excitation angles. Our results not only reveal the physical origin of the angular dispersion, but also point out a new degree of freedom to manipulate light, which are important for designing meta-devices facing versatile application requests.