title: A close-ring pair terahertz metamaterial resonating at normal incidence.
abstract: We present a systematic study of a close-ring pair based freestanding metamaterial fabricated by double-layer, self-aligned photolithography. Terahertz time-domain spectroscopy transmission measurements and numerical simulations have revealed negative index of refraction in the frequency range of 0.66-0.90 THz under normal wave incidence. The observed resonance behaviors can be well explained by a theoretical circuit model. The electromagnetic properties and the figure of merit of such close-ring metamaterials are also explored in terms of geometrical parameters of the unit cell with a goal of providing optimized design for three-dimensional metamaterials and potential device applications.
authors.affiliation: School of electrical and computer Engineering, Oklahoma State University, Oklahoma 74078, USA.
authors.forename: Jianqiang
authors.initials: J
authors.lastname: Gu
authors.forename: Jiaguang
authors.initials: J
authors.lastname: Han
authors.forename: Xinchao
authors.initials: X
authors.lastname: Lu
authors.forename: Ranjan
authors.initials: R
authors.lastname: Singh
authors.forename: Zhen
authors.initials: Z
authors.lastname: Tian
authors.forename: Qirong
authors.initials: Q
authors.lastname: Xing
authors.forename: Weili
authors.initials: W
authors.lastname: Zhang
mesh_terms: D003198:Computer Simulation; D008027:Light; D008420:Manufactured Materials; D008962:Models, Theoretical; D012031:Refractometry / Q000379:methods*; D012542:Scattering, Radiation; D055053:Terahertz Radiation