Abstract-Terahertz wave front manipulation based on Pancharatnam-Berry coding metasurface

Li Shao-he, Li Jiu-sheng, and Sun Jian-Zhong

Fig. 1. Design of the basic coding particle. (a) Schematic diagram of the basic coding particle. Reflection magnitude of the basic coding particle under normal incidence of LCP (b) and RCP (c) waves. Here, RLL(RRR) and RRL(RLR) are the reflection magnitude with co-polarization and cross-polarization under normally incident LCP (RCP) waves, respectively. (d) Reflection phase and amplitude values under normal incidence of x- and y linearly polarized waves, respectively.

https://www.osapublishing.org/ome/abstract.cfm?uri=ome-9-3-1118

We design a coding metasurface based on Pancharatnam-Berry (PB) phase to manipulate terahertz waves, which is simple and flexible. Compared with the previous design of the coding metasurface, the present coding particles can be obtained by using a same size meta-particle with various orientations instead of designing multiple structures or changing specific size parameters. The PB coding metasurfaces composed of U-shaped particles with pre-designed coding sequences can generate multi-bit coding in the terahertz frequencies and control the reflected terahertz waves to the various directions. Both simulation and theoretical calculation scattering patterns of the designed PB coding metasurfaces demonstrate the expected manipulations. Additionally, the bandwidth of radar cross section (RCS) reduction of approaching −15 dB is 1.05THz (range from 0.9THz to 1.95THz). We believe that the proposed design provides a more flexible way for the manipulation of reflected terahertz waves.

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