Abstract-Controllable Terahertz Switch Using Toroidal Dipolar Mode of a Metamaterial

 

Tong Guo, Chen Chen, Fei Yan, Ruoxing Wang,  Li Li, 

https://link.springer.com/article/10.1007/s11468-020-01359-5

We present a controllable terahertz (THz) metamaterial switch by manipulating toroidal dipolar mode in simulation. The metamaterial switch consists of periodically patterned metallic split rings with photosensitive silicon stripes. The excitation of toroidal dipolar resonance is closely dependent on the transition between the dielectric and conductive phases of photosensitive silicon. The toroidal dipolar mode is exploited to modulate the ON/OFF-switching transmission of THz wave under wide incident angles. The operation mechanism and frequency tunability are discussed.

Abstract-Dynamically tunable polarization-independent terahertz absorber based on bulk Dirac semimetals

Ming Chen, Chen Chen, Shijie Deng, Houquan Liu, Chuanxin Teng, Yu Cheng, Hongyan Yang, Ronghui Xu, Hongchang Deng, and Libo Yuan

Fig. 1. Schematic of the 3×$\times$3 unit structure of the proposed absorber which is composed of a patterned Dirac semimetal film, the dielectric layer and a metal reflector. The incident electric field is along the 𝑥$x$-axis and the magnetic field is along the 𝑦$y$-axis.

https://www.osapublishing.org/osac/abstract.cfm?uri=osac-2-8-2477

In this paper, we propose a tunable and polarization-independent absorber based on a bulk Dirac semimetal (BDS) metasurface at terahertz frequencies with a high absorption. The numerical results show that the full width at half maximum is △𝑓=9.1×10−2$△f=9.1\times {10}^{-2}$ THz. The absorption is maintained at above 95% when the Fermi level is in the range from 65 meV to 85 meV and the resonance frequency is in the range from 2.46 THz to 3.16 THz. For both polarizations, the absorption peak is maintained at above 80% for incident angles up to 60∘${60}^{\circ }$. Based on our method, various BDS-based tunable absorbers can be designed for terahertz, infrared, and visible frequencies. This significantly enhances the usefulness of these absorbers in a wide range of applications such as sensing systems and optoelectronic devices.

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