Polarization-insensitive and tunable plasmon induced transparency in a graphene-based terahertz metamaterial

• Published in: Optics communications 2018-10, Vol.424, p.163-169
• Main Authors: Huang, Hailong, Xia, Hui, Guo, Zhibo, Li, Hongjian, Xie, Ding
• Format: Article
• Language: English
• Subjects: Graphene; Plasmon induced transparency; Polarization independent; Refractive index sensor
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2018.04.060

The polarization-insensitive and tunable plasmon induced transparency (PIT) in a graphene-based terahertz metamaterial are investigated. The cross metal and four square split-ring resonators (SRRs) are used to form the polarization-insensitive metamaterial. The tunable property is obtained by loading a graphene into the structure. Numerical results show that the resonant frequency and the performance of PIT transparency window are flexibly tuned by changing the Fermi energy of graphene layer and relative distance between the cross metal and SRRs, respectively. The PIT transparency windows are maintained at any polarization angles of the incident wave. The proposed system can be used as a refractive index sensor with a sensitivity of 26.6 THz/refractive index unit (RIU) at the transparent peak, and a group delay of 0.9 ps is also obtained for slow-light application. The results show that the proposed nanostructure may find its potential applications in environmental sensors, switches and slow-light devices. •The tunable PIT peak is realized by manipulating graphene’s Fermi energy.•The PIT transparency window can be maintained at any polarization angles.•Realizing group delay of about tg=0.9 ps.•The PIT device exhibits an intensity modulation efficiency of 75%.