Xiaoyong He1 and Hongxia Lu2
1 Mathematics & Science College, Shanghai Normal University, No. 100 Guilin Rd., Shanghai, 200234, People's Republic of China
2 School of Material Science and Engineering, Zhengzhou University, No. 100 Science Rd., Zhengzhou, Henan, 450001, People's Republic of China
2 School of Material Science and Engineering, Zhengzhou University, No. 100 Science Rd., Zhengzhou, Henan, 450001, People's Republic of China
By depositing a graphene layer on the metallic film with subwavelength hole arrays, the tunable extraordinary transmission property based on the metal-dielectrics-graphene (MDG) structure has been investigated in the terahertz (THz) and near-infrared (NIR) regimes. The influences of operation frequency, composed materials, and the Fermi level of the graphene layer have been taken into account. The results show that by varying the Fermi level of the graphene layer, the transmission of the MDG structure can be tuned in a wide range and the modulation depth of the peak value of the transmission can reach more than 50%. But the tunable mechanisms in the THz and NIR regimes are quite different. In the infrared (THz) regime, the graphene behaves like the dielectric (metallic) layer; its dielectric constant decreases (increases) with the increase of Fermi level, resulting in the transmission increasing (decreasing). Compared with the metallic structure, the transmission of the semiconductor structure can also be modulated by using the doping or varying temperature; its peak position can also be changed in a much broader range. The results are very useful to understand the mechanism of the graphene plasmonic devices and to design novel filters, switchers, modulators, and sensors.
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