Design, simulation, and characterization of THz metamaterial absorber

In recent years a great amount of research has been focused on metamaterials, initially for fabrication of left-handed materials (LHM) for use in devices such as superlenses, or electromagnetic cloaking device. [1, 2]. Such devices have been developed and demonstrated in regimes from radio frequency all the way up to infrared and near optical frequencies [3-5]. Metamaterials can be characterized by electric permittivity, ε(ω), and magnetic permeability, μ(ω). By manipulating these properties, metamaterials can be engineered to exhibit un-natural phenomena such as negative index of refraction (n <; 0). Furthermore, the electric and magnetic responses of metamaterials can be independently adjusted which provides a significant advantage over conventional materials to allow a convenient method to develop a wide range of devices. More recently, it has been shown that by careful adjustment of ε(ω) and μ(ω), near perfect electromagnetic absorbers can be realized [6, 7]. High absorption occurs when transmission and reflection are simultaneously minimized. With some clever tuning of the electric and magnetic responses, the electric and magnetic energy may both be absorbed by a metamaterial structure. By independently adjusting ε(ω) and μ(ω) such that the effective impedance of the metamaterial is matched to that of free space (Z_eff = Z₀), the reflection at some resonance frequency, ω₀, can be minimized.