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-Graphene/liquid crystal hybrid tuning terahertz perfect absorber

Ruoxing Wang, Li Li, Tong Guo, Tianzhi Wang, Jianlong Liu, Hao Tian, Fengjun Tian, and Weimin Sun

https://www.osapublishing.org/ao/abstract.cfm?uri=ao-58-34-9406

We present, by simulations, a metastructured graphene/liquid crystal hybrid tuning terahertz perfect absorber that consists of graphene disk resonator arrays above a metallic layer separated with liquid crystal substrate. The liquid crystal refractive index and the graphene Fermi level are utilized to implement double-tuning operation to push the spectra scanning limit of the terahertz absorber. Our simulations demonstrate high performance of a near-linear broad tuning region and near-unity absorbance with wide incident angle and polarization independence. The range of the resonant frequency scan is notably enlarged at a spectral ratio of as high as Δ𝑓/𝑓=50%$\mathrm{\Delta }f/f=50\mathrm{\%}$ while ensuring absorbance beyond 90%. Such graphene/liquid crystal hybrid tuning scheme would be preferable to push the working-band limit of terahertz perfect absorbers.

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