A polarization-insensitive tunable electromagnetically induced transparent terahertz device

Abstract

The invention belongs to the field of metamaterial structures, in particular to a polarization-insensitive tunable electromagnetically induced transparent terahertz device. The device is composed of a substrate, a graphene layer, a metal layer and a metal electrode; the substrate includes a silicon layer and a silicon dioxide layer covering the silicon layer; the graphene layer covers the upper surface of the silicon dioxide layer , and the graphene layer is composed of periodically arranged graphene frame structures; the metal layer covers the upper surface of the silicon dioxide layer, and the metal layer is composed of periodically arranged cross-shaped metal unit structures; One electrode of the metal electrode is arranged at the edge of the graphene layer and connected with the graphene layer, and the other electrode is arranged at the edge of the silicon layer and connected with the silicon layer. The invention can realize electromagnetically induced transparency and generate slow light effect. The invention can realize the regulation of the transmission characteristics and slow light effect of metamaterial devices by applying external bias voltage, and effectively adjust the size of the group delay.

Description

technical field [0001] The invention belongs to the field of metamaterial structures, and in particular relates to a polarization-insensitive adjustable electromagnetically induced transparent terahertz device. Background technique [0002] Electromagnetically induced transparency is a coherent process in an atomic system. It refers to the interference of energy level transitions generated by an external light beam in an originally opaque material, making it transparent in a very narrow frequency band. window. This phenomenon is accompanied by strong dispersion and frequency selection, which can produce slow light effects and filtering characteristics. Using metamaterials to simulate electromagnetically induced transparency in atomic systems overcomes the harsh conditions required in atomic systems such as low temperature, optical pumping, and metal gas environments. Through structural design, electromagnetic waves can excite bound modes on the surface of metamaterials, re...

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Problems solved by technology

[0004] Existing designs of electromagnetically induced transparent metamaterials based on polarization insensitivity are often based on common metal periodic structures. Although the designed metamaterial devices have the characteristics of insensitivity to incoming wave polarization, they are not sensitive after the design is completed. Does not have the group delay adjustment function, which is easily limited in practical applications

At present, there are already some metamaterial devices based on graphene-metal composite structure, which can generate group delay through electromagnetically induced transparency, and the transmission characteristics can be adjusted by means of electrical adjustment. The existing technology can be adjusted by applying an external voltage. Group delay function, but because the realization of electromagnetically induced transparency often requires an asymmetric structure of the unit, it is difficult to achieve symmetry in the unit structure, and it is impossible to achieve the same effect on incoming waves of different polarizations

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