title: Optimizing low loss negative index metamaterial for visible spectrum using differential evolution.
abstract: A novel negative index metamaterial design methodology for the visible spectrum with low losses was presented in this paper. A robust differential evolution (DE) was employed to optimize the metamaterial design to achieve a desired set of values for the index of refraction. By using numerical simulation of a wedge-shaped model and S-parameter retrieval method, we found that the DE-designed optimal solution can exhibit a low loss LH frequency band with simultaneously negative values of effective permittivity and permeability at the violet-light wavelength of 408 nm, and the figure of merit is 15.2, that means it may have practical applications because of its low loss and high transmission. Therefore, the design methodology presented in this paper is a very convenient and efficient way to pursue a novel metamaterial with desired electromagnetic characteristics in the visible spectrum.
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, China.
authors.forename: Yongxiang
authors.initials: Y
authors.lastname: Zhao
authors.forename: Fei
authors.initials: F
authors.lastname: Chen
authors.forename: Qiang
authors.initials: Q
authors.lastname: Shen
authors.forename: Qiwen
authors.initials: Q
authors.lastname: Liu
authors.forename: Lianmeng
authors.initials: L
authors.lastname: Zhang