Abstract-Tunable terahertz hybrid graphene-metal patterns metamaterials

Chenyuyi Shi, Xiaoyong He, Jun Peng, Guina Xiao, Feng Liu, Fangting Lin, Hao Zhang,



https://www.sciencedirect.com/science/article/pii/S0030399218317250

Based on the hybrid metal-graphene structures, we investigated the tunable Fano resonances in the terahertz region, including the effects of graphene Fermi levels, structural parameters, and operation frequencies. The results reveal that an obvious Fano resonance can be observed, the maximum peak value of Fano resonance can reach 0.9711, and its Q-quality factor is more about 20. With the help of the graphene layer, the resonant curves of the proposed structures can be effectively modulated, the frequency modulation depth can reach 60% as the Fermi level changes in the range of 0.1–1.0 eV. In addition, by varying the length of graphene bar in the scope of 10–60 μm, the amplitude modulation depths are about 21.0%. The results are helpful for designing novel graphene-based tunable terahertz devices with high Q factor, e.g. modulators, sensors and antenna.

Abstract-Graphene patterns supported terahertz tunable plasmon induced transparency

Xiaoyong He, Feng Liu, Fangting Lin, and Wangzhou Shi

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-26-8-9931

The tunable plasmonic induced transparency has been theoretically investigated based on graphene patterns/SiO2/Si/polymer multilayer structure in the terahertz regime, including the effects of graphene Fermi level, structural parameters and operation frequency. The results manifest that obvious Fano peak can be observed and efficiently modulated because of the strong coupling between incident light and graphene pattern structures. As Fermi level increases, the peak amplitude of Fano resonance increases, and the resonant peak position shifts to high frequency. The amplitude modulation depth of Fano curves is about 40% on condition that the Fermi level changes in the scope of 0.2-1.0 eV. With the distance between cut wire and double semi-circular patterns increases, the peak amplitude and figure of merit increases. The results are very helpful to develop novel graphene plasmonic devices (e.g.sensors, modulators, and antenna) and find potential applications in the fields of biomedical sensing and wireless communications.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-Investigation of graphene-supported tunable asymmetric terahertz metamaterials

Chenyuyi Shi, Xiaoyong He, Feng Liu, Fangting Lin, and Hao Zhang

https://www.osapublishing.org/josab/abstract.cfm?uri=josab-35-3-575

By integrating a graphene layer with asymmetric split-ring metamaterial (MM) metal resonators, we investigated tunable propagation properties in the terahertz regime, including the effects of graphene Fermi levels, structural parameters, and operation frequencies. The results reveal that a sharp inductor-capacitor (LC) resonance can be observed at low frequency for the asymmetric MM structure, and its 𝑄$Q$ factor can reach more than 17.5. With the help of a graphene layer, the optical response is modulated efficiently. For instance, if the Fermi level changes in the range of 0.01–0.3 eV, for the semiconductor MM structure, the modulation depths (MDs) of amplitude and frequency are 27.0% and 43.4%, respectively. In addition, the resonant curves of indium antimonide (InSb) MMs can be modulated by changing the temperature; the amplitude MD is 56.2% as the temperature changes in the range of 350–800 K. The 𝑄$Q$ factor of the InSb MM structure is about 44.6. The results are helpful for designing novel graphene-based tunable terahertz devices, e.g., filters and modulators.

© 2018 Optical Society of America

Abstract-Investigation of graphene assisted tunable terahertz metamaterials absorber

Xiaoyong He, Xu Zhong, Fangting Lin, and Wangzhou Shi
http://proxy.osapublishing.org/ome/abstract.cfm?uri=ome-6-2-331

By using the graphene-SiO2-Si-dielectrics-metallic ground plane (GSiO2SiDM) structures, we investigate the tunable properties of graphene metamaterials (MMs) absorbers in the terahertz region, including the effects of operation frequency, Fermi level, and graphene structure patterns. The results manifest that the graphene tunable GSiO2SiDM structure can achieve net absorption by changing structure parameters and the Fermi level of graphene layer. The resonant absorption and reflection curves of the GSiO2SiDM structures can be shifted in a wide range via controlling the applied electric fields. The modulation depth of resonant amplitude and frequency can reach more than 60% and 30%, respectively. The resonant peak (dip) of the absorption (reflection) curves shift to high frequency with the increase of Fermi level of the graphene layer. Due to broad absorption curve, the graphene MMs absorbers structures are suitable for the fabrication of broad absorber. The results are very useful to design novel devices, such as thermal detectors, imager, and biosensors.

© 2016 Optical Society of America

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