Multiple-band metamaterial absorber at terahertz regime using periodically arranged surface structure placed on ultra-thin thickness of insulating dielectric slab backed by a metallic ground plane is demonstrated in this paper....

This paper presents the design of triple-band terahertz metamaterial absorber, whose surface structure is a nested-type metallic pattern composed of two pairs of splitting arcs, of which the inner two splitting arcs have the same but smaller size, while the outer two possess the same but larger dimension. The surface patterned structure can strongly interact with the incident terahertz beam, resulting in three narrow-band and discrete resonance peaks having higher than 94% absorption rates. Near-field patterns of the three absorption peaks are discussed to insight into the physical mechanism of these peaks, it is revealed that the first two absorption peaks result from the dipole resonance of the inner two splitting arcs and outer pair of splitting arcs, respectively, while the last absorption peak is caused by surface propagation resonance of the surface patterned resonator. The effect of structure parameters, including the sizes of splitting arcs and the spacing between two pairs of splitting arcs, on the absorption properties, is further analyzed. The absorber suggested here could provide guidance for the design of multiple-band metamaterial absorbers, and could find great application prospects in terahertz technology-related areas.

Quad-band terahertz metamaterial absorber with near-perfect absorption is given in this paper. It is designed by a patterned Au layer and a continuous Au film separated by an insulating dielectric layer, of which the patterned Au layer is consisted of three parallel Au strips (a longer and two shorter) surrounded by two Au ring arcs of the same size. Four separated terahertz absorption peaks with narrow bandwidths and large absorptance are realized. The first three absorption peaks are due to the fundamental modes of the Au strips and the Au ring arcs, while the fourth absorption peak is ascribed to the excitation of three-order resonance in the Au ring arcs. The field distributions of the four absorption peaks are presented to verify their physical mechanisms. The influence of geometrical dimensions of the proposed configuration on the performance of the quad-band light absorption is discussed. Moreover, considering the potential sensing applications, the sensing performance of the proposed absorption device is also explored. The suggested scheme could provide considerable application prospects in selective thermal radiation, spectral imaging, sensing, detecting, electromagnetic stealth, etc.

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