Abstract
In this paper, we demonstrate an ultra-broadband terahertz bilayer graphene-based absorption structure. It has two stacking graphene layers sandwiched by an Au cylinders array, backed by a metallic ground plane. Au cylinders are used to adjust the input impedance to be closely matched to the free space, enabling an ultra-broadband absorption. The absorption spectrum of the bilayer graphene-based absorption structure with Au cylinder arrays shows a bandwidth of 7.1 THz, with the absorption exceeding 80%. The achieved ultra-wideband THz meta-absorber has high absorption, independence of polarization property, simultaneously, illustrating to be a promising candidate for teraherz broadband absorption application.
Highlights
The terahertz (THz) range of the electromagnetic spectrum, located between microwave and infrared band, has received fast growing research interest in the past two decades, due to extensive applications such as safety inspection, imaging, sensing, material detection, secure communication and so on in virtue of its unique properties [1,2,3,4,5]
Motivated by the methods and structures of researches to achieve broad angle [26,27], and high absorption [28,29], and driven by the essential need for polarization-independent ultra-wideband meta-absorber, we theoretically investigate a bilayer graphene-based absorption structure with Au cylinder arrays on parylene substrate
The second graphene layer is set as impedance boundary2 with resistance2: 1/co f f2 /τ2, and reactance2: 2πFreq/co f f2
Summary
The terahertz (THz) range of the electromagnetic spectrum, located between microwave and infrared band, has received fast growing research interest in the past two decades, due to extensive applications such as safety inspection, imaging, sensing, material detection, secure communication and so on in virtue of its unique properties [1,2,3,4,5]. The THz absorbing structure has been part of important elements in these. Limited by the lack of natural absorbing materials in the terahertz gap, metamaterial absorbers (MAs), where the periodic elements are much smaller than the working wavelength of THz waves, have been considered to be an effective solution [6,7,8,9,10]. According to the equivalent medium theory, by reducing transmission and reflection, the energy of the electromagnetic wave is confined in the material, illustrating absorption characteristics
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