Abstract-Terahertz tunable graphene Fano resonance

Xiaoyong He1,2, Fangting Lin1, Feng Liu1 and Wangzhou Shi1

http://iopscience.iop.org/article/10.1088/0957-4484/27/48/485202/pdf
By depositing graphene circular double rings (DR) on a SiO2/Si/polymer substrate, the tunable Fano resonance has been theoretically investigated in the terahertz regime, including the effects of the graphene Fermi level, structural parameters and operation frequency. The results demonstrate that the obvious Fano peak can be efficiently modulated because of strong coupling between the incident waves and graphene ribbons. As the Fermi level increases, the peak amplitude of the Fano curve increases, and the resonant peak position shifts to a high frequency. The amplitude modulation depth of the Fano curves is about 30% if the Fermi level changes in the scope of 0.1–1.0 eV. The optimum gap distance between the DR is about 8–12 μm, where the value of the figure of merit shows a peak. The results are very helpful in order to develop novel graphene plasmonic devices, e.g. sensors and modulators.

Abstract-Investigation of the tunable properties of graphene complementary terahertz metamaterials

Xiaoyong HE,   Chunlin Liu,   Xu Zhong and   Wangzhou Shi  

RSC Adv., 2015, Accepted Manuscript

DOI: 10.1039/C4RA16762G
Accepted 09 Jan 2015
First published online 13 Jan 2015
http://pubs.rsc.org/en/content/articlelanding/2015/ra/c4ra16762g#!divAbstract

Based on the graphene-SiO2-Si structure, the tunable resonant properties of the complementary graphene metamaterials (MMs) have been investigated in the terahertz regime. The influence of operation frequency, the Fermi levels of graphene layer, and different kinds of graphene patterns have been taken into account. The results manifest that the tunable mechanisms of the complementary graphene MMs structures mainly depend on the LC resonance. The resonant transmission and reflection properties of the complementary graphene MMs structures can be tuned in a wide range via controlling the applied electric fields. As the Fermi level of graphene layer increases, the resonances of the MMs structure become stronger, and the resonant peaks of the transmission curves shift to the higher frequency, resulting from the permittivity of graphene layer increases in the THz regime. The transmission (reflection) spectrum is broad (sharp), which can be used to fabricate transmission modulator (reflection filters). The results are very helpful to design novel plasmonic devices and useful for the application of biomedical sensing and optical communications.


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