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.

© 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-Terahertz wave polarization splitter using full band-gap photonic crystals

Sun Jian-zhong,  

Li Jiu-sheng

http://link.springer.com/article/10.1007/s10762-014-0131-7

Manipulation of terahertz wave polarization state exhibits tremendous potential in developing application of terahertz science and technology. A terahertz polarization beam splitter based on three linear defect photonic crystal waveguides is designed and numerically demonstrated. Both plane wave expansion method and finite-difference time-domain method are used to calculate and analyze the characteristics of the proposed device. The simulation results show that the designed polarization beam splitter can split TE and TM polarized mode into different propagation directions with high efficiency in the frequency range from 1.225THz to 1.260THz. Especially, the extinction ratios for both TE and TM modes are larger than 20dB.