Recent advances in hyperbolic metamaterials have spurred many breakthroughs in the field of manipulating light propagation. However, the unusual electromagnetic properties also put extremely high demands on its compositional materials. Limited by the finite relative permittivity of the natural materials, the effective permittivity of the constructed hyperbolic metamaterials is also confined to a narrow range. Here, based on the proposed concept of structure-induced spoof surface plasmon, we prove that arbitrary materials can be selected to construct the hyperbolic metamaterials with independent relative effective permittivity components. Besides, the theoretical achievable ranges of the relative effective permittivity components are unlimited. As proofs of the method, three novel hyperbolic metamaterials are designed with their functionalities validated numerically and experimentally by specified directional propagation. To further illustrate the superiority of the method, an all-metal low-loss hyperbolic metamaterial filled with air is proposed and demonstrated. The proposed methodology effectively reduces the design requirement for hyperbolic metamaterials and provides new ideas for the scenarios where large permittivity coverage is needed such as microwave and terahertz focus, super-resolution imaging, electromagnetic cloaking, and so on.
تحميل البحث