A polarization- and angle-insensitive broadband tunable metamaterial absorber using patterned graphene resonators in the terahertz band. (December 2020)

• Record Type: Journal Article
• Authors: Du, Xuemei; Yan, Fengping; Wang, Wei; Tan, Siyu; Zhang, Luna; Bai, Zhuoya; Zhou, Hong; Hou, Yafei
• Is Part Of: Optics & laser technology. Volume 132(2020)
• Publication Date: 2020-12
• Subjects: Patterned-graphene -- Surface plasmon resonance -- Broadband metamaterial absorber -- Tunability -- Insensitivity; Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2020.106513
• Languages: English
• ISSNs: 0030-3992

Abstract

Highlights: A broadband metamaterial absorber has been proposed based on the patterned graphene resonators. The bandwidth of the proposed absorber reaches 2.76 THz with the absorptivity over 90%. The broad absorption bandwidth (ABW) of the proposed absorber is about 79.2%. The proposed structure can be dynamically tuned to act as an absorber or reflector. Abstract: The emerging material of graphene has resulted in new options for the design of metamaterial devices with excellent performances, offering an attractive platform for electromagnetic absorption applications. To date, researches on patterned graphene-based metamaterial absorbers (MAs), have focused on achieving broadband absorption while maintaining many excellent properties. Here, we propose a broadband tunable MA with a perfect absorption based on a novel design of the combination of cross- and square-shaped graphene sheets. Numerical simulation results show that the bandwidth of the proposed broadband MA reaches 2.76 THz with the absorptivity greater than 90% for both the transverse electric (TE) and transverse magnetic (TM) modes, which exceeds most of broadband absorption results achieved by MAs in previous studies. A numerical analysis employing the equivalent circuit model for the designed structure is conducted to determine the influence of the structural parameters on the absorptivity and optimize the parameters. Results show that impedance matching is achieved between the input impedance and the free-space impedance at the absorption band. Detailed numerical simulations are conducted to calculate the surface loss density, electric field, and surface currents to obtain an understanding of the high absorption mechanism. Also, the designed MA exhibits excellent properties, such as tunability, polarization independence, incident angle insensitivity and outstanding tolerance to changes in the structural parameters, suggesting that the proposed absorber is a promising candidate for various applications in the terahertz band.