Fei Gao, Zhihong Zhu, Wei. Xu, Jianfa Zhang, Chucai Guo, Ken Liu, Xiaodong Yuan, and Shiqiao Qin
https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-9-9579
We present a wave absorption design consisting of periodical arrays of dielectric bricks on the dielectric substrate, which is coated with single-layered and nonstructured graphene, supported by a thick piece of metal. The design is demonstrated to broadband near-perfect absorption with 0.82 terahertz (THz) bandwidth of over 90% absorption and with central frequency of 1.68 THz. The broadband absorption mechanism originates from two contributions. Firstly, the periodical arrays of dielectric bricks on the nonstructured graphene can provide both a set of graphene plasmon resonances with large relative frequency interval and relative radiation rate γ/ω in the THz range. Secondly, the linewidth of each resonance can be broadened by the far-field interaction between neighboring resonators to overlap and spread over a wide frequency region in the THz range. The design in this paper is simple, and consequently facilitates the fabrication and promotes the application of broadband graphene absorbers.
© 2017 Optical Society of America
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