Electromagnetic characterization of planar metamaterials by oblique angle spectroscopic measurements


Journal Article

Artificially structured metamaterials with unit-cell dimensions on the order of 1 10th of a wavelength (λ 10) have been shown to be well approximated by an effective medium description which mimics a continuous material. In this paper we present data for transmission and reflection from a planar array of split-ring resonators (SRRs) at varying angles of incidence. We attempt to model the form of the angle-dependent response of the SRRs using the Fresnel equations formulated from effective medium theory-treating the array as a thin continuous anisotropic crystal. This model is then fit to experimental data taken on a planar array of split rings to gauge the model accuracy, and to produce values for the frequency-dependent permeability and permittivity of the experimental SRR array. Simultaneous fitting of the transmission and reflection at multiple angles helps to avoid multiple solutions for the permittivity and permeability. This forward fitting approach using multiple angles is advantageous, as it enables a characterization of the optical constants without the need for phase information, and it avoids many of the branch problems inherent in the numerical inversion methods used so far on metamaterials. The work presented here shows the feasibility of this method. A refined procedure will be particularly advantageous for experimental characterization of higher frequency structures (i.e., THz and above), where phase information is difficult or impossible to obtain. © 2007 The American Physical Society.

Full Text

Duke Authors

Cited Authors

  • Driscoll, T; Basov, DN; Padilla, WJ; Mock, JJ; Smith, DR

Published Date

  • March 13, 2007

Published In

Volume / Issue

  • 75 / 11

Electronic International Standard Serial Number (EISSN)

  • 1550-235X

International Standard Serial Number (ISSN)

  • 1098-0121

Digital Object Identifier (DOI)

  • 10.1103/PhysRevB.75.115114

Citation Source

  • Scopus