三維奈米裂環共振器於各向同性完美吸收體之研究

Abstract

超穎材料是一種幾乎不存在於自然界的特殊人造材料，此種材料的特性主要取決於其組成單元的結構，而不是完全由其組成的物質所決定。本文利用電子束微影技術於矽基板上製作三維直立式裂環共振器，並利用此三維直立式裂環共振器製作完美吸收體，結構採用金屬介電質金屬的三層結構，最下層鍍金膜反射鏡，中間以ZnS-SiO2作為介電層，最上層以直立式裂環共振器作為與入射光波交互作用之結構，運用此結構的優勢在於直立式裂環共振器可同時吸收入射光電場與磁場所帶有之能量，以增強吸收效果，並將其以十字型對稱排列，使其在垂直入射光下有近乎完美的各向同性，模擬上可達到超過99%的入射光吸收率，並且在TE與TM波斜向入射情況下，正負60度內亦有良好的吸收表現。

Metamaterials are artificial materials which cannot be found in nature. The properties of these materials are not from the component but from the artificial structures in subwavelength scale. In this thesis, we use ebeam lithography to make the three dimensional erected split-ring resonators, and fabricate metamaterial perfect absorber by the three dimensional erected split-ring resonators. We adopt the metal-insulator-metal(MIM) structure. The button layer is a gold layer as a mirror, and the middle layer is ZnS-SiO2. The top layer adopts erected split-ring resonators to serve as the structure interacting with the incident light. The benefit of using the erected split-ring resonators is that the erected split-ring resonators can coupling the energy of electric and magnetic field at the same time which can enhance the absorption. Then we arranged the erected split-ring resonators in cross-shaped which makes this structure isotropic when direct illumination. Also, the electromagnetic response still keeps in a great absorption under both TM- and TE-polarized illumination even through the angle of incidence is greater than 60 degrees.