Abstract-Terahertz high-resolution wideband focusing metasurface based on catenary structure

Ruoyu Shi, Jiao Jiao, Jisheng Tong,  Yong Bo, Leijun Zhang, Chao Xiong, Qing Zhao



https://www.sciencedirect.com/science/article/abs/pii/S0030401819303323

Due to several excellent properties, electromagnetic terahertz waves may be very useful for imaging applications, provided sufficiently high-resolution can be achieved. A tightly focused beam can be produced using a two-dimensional metasurface and catenary structure that enables phase-tuning of electromagnetic waves. We modified the catenary structure to produce a metasurface and a non-diffracting 0th -order Bessel beam. According to our calculation, the formed wideband focal spots can be smaller than Abbe’s diffraction limit, between 350 GHz and 450 GHz, with a maximum gain of 15.1 dB. Such a metasurface could open new doors for future high-resolution medical imaging research and technology.

Abstract-Theoretical and Experimental Studies of Terahertz Wave Propagation in Unmagnetized Plasma

• Ling Zheng, 
• Qing Zhao, 
• Shuzhang Liu, 
• Xiaojun Xing, 
• Yuxu Chen

http://link.springer.com/article/10.1007%2Fs10762-013-0035-

The spacecraft will experience the well-known “blackout” problem when it re-entry into the Earth’s atmosphere, which results in communication failures between the spacecraft and the ground control center. It is important to study the properties of terahertz (THz) wave propagation in plasma for communications using THz wave is an alternative method for solving the blackout problem. The properties of THz wave propagation in plasma have been studied with the ZT-FDTD (Z-Transform Finite Difference Time Domain) method and experimental method in this paper. The dependence of plasma density, plasma collision frequency, thickness of plasma and THz wave frequency on the THz wave propagation are presented. The properties of 0.22THz electromagnetic wave propagation in plasma have been studied experimentally with shock tube, and the experimental results are in good agreement with the FDTD ones. Both the FDTD and experimental results indicate that communications using THz wave is an alternative and effective way to solve the blackout problem.