Abstract- Stochastic Polynomial Chaos Expansion Analysis of a Split-Ring Resonator at Terahertz Frequencies

 Huludsi Acikgoz,   Raj Mittra

https://ieeexplore.ieee.org/document/8279392/

Polynomial chaos expansion (PCE) technique is applied to a conducting array of split-ring resonator to study the effect of the uncertainties of its design parameters on its reflectance at terahertz frequencies. The uniformly distributed random input design parameters have been considered. The first (average) and second (standard deviation) moments are estimated using the PCE. Strong variation of the output response caused by the uncertainties of the design parameters has been noticed. A sensitivity analysis has been carried out to assess the influence of each input parameters on the reflectance. The results show the effectiveness of the PCE and demonstrate that the PCE can be a useful statistical tool to analyze electromagnetic structures.

Abstract-Plasmon induced transparency in graphene based terahertz metamaterials

Koijam Monika Devi, M. Islam, Dibakar R. Chowdhury, Amarendra K. Sarma, Gagan Kumar

https://arxiv.org/abs/1711.03775

Plasmon induced transparency (PIT) effect in a terahertz graphene metamaterial is numerically and theoretically analyzed. The proposed metamaterial comprises of a pair of graphene split ring resonators placed alternately on both sides of a graphene strip of nanometer scale. The PIT effect in the graphene metamaterial is studied for different vertical and horizontal configurations. Our results reveal that there is no PIT effect in the graphene metamaterial when the centers of both the split ring resonators and the graphene strip are collinear to each other. This is a noteworthy feature, as the PIT effect does not vanish for similar configuration in a metal-based metamaterial structure. We have further shown that the PIT effect can be tuned by varying the Fermi energy of graphene layer. A theoretical model using the three level plasmonic system is established in order to validate the numerical results. Our studies could be significant in designing graphene based frequency agile ultra-thin devices for terahertz applications.

Abstract-Tailoring the plasmon-induced transparency resonances in terahertz metamaterials

Meng Liu, Zhen Tian, Xueqian Zhang, Jianqiang Gu, Chunmei Ouyang, Jiaguang Han, and Weili Zhang

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-17-19844


We experimentally demonstrate that a coupled metamaterial composed of sub-wavelength split-ring-resonators (SRRs) and closed-ring-resonators (CRRs) can tailor the plasmon-induced-transparency (PIT) resonances when the external electric field is parallel to the gaps of SRRs. Rotating or moving SRRs in vertical direction plays a critical role in the EIT functionality, while an excellent robust performance can be acquired via moving SRRs in the horizontal direction. Based on the results, a polarization-independent and polarization-dependent planar metamaterial are designed, fabricated and measured. In contrast to the spectral property of the polarization-independent medium, the polarization-dependent one is featured by isolated PIT phenomena in the frequency-domain, with respect to the horizontal and vertical polarized incident beam. Transmission responses of the PIT metamaterial are characterized with terahertz time-domain spectroscopy, showing a good agreement with the rigorous numerical simulation results. The presented work delivers a unique way to excite and modulate the PIT response, toward developing polarization-independent and polarization-dependent slow-light building blocks, ultrasensitive sensors and narrow-band filters functioning in the THz regime.

© 2017 Optical Society of America

Abstract-Characteristic analysis of a photoexcited metamaterial perfect absorber at terahertz frequencies

Pibin Bing, Shichao Huang, Zhongyang Li, Zhou Yu, Ying Lu, Jianquan Yao

http://www.worldscientific.com/doi/abs/10.1142/S0217984917502074

The absorption characteristics of a photoexcited metamaterial absorber at terahertz frequencies were analyzed in this study. Filling photosensitive semiconductor silicon into the gap between the resonator arms leads to modulation of its electromagnetic response through a pump beam which changes conductivity of silicon. Comparisons of terahertz absorbing properties which were caused by different thicknesses and dielectric constants of polyimide, cell sizes and widths of SRRs, and lengths and conductivities of the photosensitive silicon, were studied by using Finite Difference Time Domain (FDTD) from 0.4 THz to 1.6 THz. The results of this study will facilitate the design and preparation of terahertz modulator, filters and absorbers.