Composite silicon hemisphere/graphene broadband terahertz metamaterial absorber

Abstract

The invention discloses a broadband terahertz metamaterial absorber based on composite silicon hemispheres / graphene, and belongs to the technical field of metamaterials and electromagnetic functional materials. The terahertz metamaterial absorber comprises a metal reflecting layer, a dielectric layer, a graphene layer and a silicon hemisphere layer. The metal reflecting layer is a continuous metal film, and the thickness of the metal reflecting layer is larger than the skin depth of working terahertz waves. The dielectric layer is located between the metal reflecting layer and the graphene layer and is a polydimethylsiloxane (PDMS) film; and a silicon hemisphere layer is loaded on the unpatterned graphene layer and is formed by periodically arranging compounded semi-ellipsoids and semi-spheres, and each period comprises four semi-ellipsoids which are rotationally symmetrical and a semi-sphere structure in the center. By reasonably designing the geometric dimension of the silicon hemisphere and the external voltage value of the graphene, the characteristic of completely absorbing electromagnetic waves vertically incident to the surface of the metamaterial can be realized. The structure is simple, a multi-layer stacking structure is not needed, and the broadband high-absorption characteristic is achieved.

Description

Technical field: [0001] The invention belongs to the technical field of metamaterials and electromagnetic functional materials, and relates to a terahertz absorber, in particular to a composite silicon hemisphere / graphene broadband terahertz metamaterial absorber. Background technique: [0002] The frequency range of terahertz wave (THz) is about 0.1-10THz (the wavelength range is about 3mm-30μm), which is located between microwave and infrared. It has very rich physical properties, such as strong absorption of water, strong absorption of water, and Its transparency, recognition of bio-organic macromolecules, and harmless ionization of biological tissues make it widely used in security inspection, communication, and biomedical fields. However, because there are few substances that can respond to THz waves in nature, the research on it is still very scarce. The biggest research bottleneck is the lack of detectors capable of generating effective THz responses, which greatly h...

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Problems solved by technology

Although the above two methods can broaden the absorption bandwidth to a certain extent, because both need to pattern graphene, the resulting edge effect makes the maximum absorption rate generally not higher than 90%, which limits its absorption performance. play

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