Oblique incident achromatic cloaking based on all-dielectric multilayer frame metasurfaces

Based on the generalized Snell’s law, an achromatic cloaking device with oblique incidence based on multilayer frame metasurfaces is proposed. The cloaking device consists of three layers of metasurface structures, which have functions of beam deflection, steering, and collection, respectively. To solve the problems of ohmic loss and high temperature resistance of metal structure, all-silicon dielectric material is used to design the metasurface unit structures. The linear dispersion and phase gradient of the unit structures can be controlled simultaneously by changing the dimension parameters of the all-silicon dielectric unit structures, so that the electromagnetic waves with different frequencies of oblique incidence can deflect around the cloaking object without scattering. At the frequencies of 0.375 and 0.75 THz, the simulation results show that the designed device can achieve the function of oblique incidence achromatic cloaking, and reduce the influence of chromatic dispersion on the metasurface cloaking device. The structures and methods used in this paper not only enrich the functions and types of metasurface devices, but also lay a foundation for the development of achromatic cloaking metasurface, which has a certain development prospect in radar, hallucinatory optics, perfect lens, and other fields.