太赫兹波段树枝状三维各向同性左手材料设计及特性研究

基于微波段二维树枝状左手材料的设计思想,设计了太赫兹波段的三维各向同性左手材料结构单元模型.采用金属Drude模型,运用等效媒质理论,仿真模拟了结构单元的电磁响应特性,计算了结构单元的有关电磁参数,分析了其缺陷效应和吸波特性.结果表明折射率在太赫兹波段1.17¹.38 THz之间为负值,并通过模拟负折射验证了其左手特性;在缺陷严重情况下,其左手特性将消失;通过对模型进行改进,在1.47 THz处出现了一个吸收峰,吸收率高达98%.该模型结构简单,研究结果为采用自上而下的方法制备三维太赫兹波段左手材料指出了途径.

Isotropic Left-handed Metamaterials in THz Band

Based on the designing concept of two-dimensional dendritic left-handed metamaterials in microwave band, we design the structure unit model of three dimensional isotropic left-handed metamaterials in the THz band. Adopting the metallic Drude＇s principle and effective medium theory, we simulate its electromagnetism response characteristics, compute its electromagnetism parameters and analyze its defect effect and absorption property. The results show that the refractive index between 1.17 - 1.38 THz is negative. We confirme its left-handed character- istic by simulating its negative refection. In the case of serious defect, the left-handed feature will disappear. An absorption peak appears at 1.47 THz by improving the model, the absorption rate up to 98%. The structure unit de- signed in this paper has the advantages of simplicity and isotropy. The research results provide a way to prepare three dimensional left-handed metamaterials in the THz band using the top-down approach.