Omnidirectional rectangular beam steering for terahertz waves based on Pancharatnam-Berry phase encoding metasurfaces

In order to achieve efficient and flexible manipulation of transmitted beams, we propose an all-dielectric encoded particle metasurface using the Pancharatnam-Berry phase principle. After a precise analysis of the coded particle arrangement, we propose a back-shaped coded arrangement to achieve the scattering properties of a square beam. We introduce the Fourier convolution principle in digital signal processing into the coding metasurface, and perform the addition operation on the coding sequences to realize the flexible regulation of the square scattered beam. In order to achieve consistency between the numerical simulation and the theoretical analysis, we propose an error analysis theory for rectangular beams. The model is established by mathematical geometry method, the approximate error in numerical simulation is corrected, and a method to realize standard rectangular beam is theoretically given.