Figure 3
Comparison of three-dimensional numerical and simplified matrix models for an asymmetric split ring (ASR) metamaterial. (a) Au-on-Si3N4 metamaterial unit cell geometry used in finite element numerical simulations, which employ a Drude–Lorentz model for gold, assign a fixed refractive index of 2.0 to silicon nitride (zero losses), and utilize periodic boundary conditions in the x and y directions (i.e., assume an infinite planar metamaterial array). Unit cell size p=430 nm; linewidth w=40 nm; arm and gap sizes h, g=140 nm. (b, c) Computationally modeled single-beam absorption A, reflection R and transmission T spectra for waves α and β, which are normally incident respectively on the dielectric membrane side and the metal film side of a gold/silicon nitride ASR metamaterial. (d) A, R and T spectra calculated using a simplified, propagation direction-independent single-beam scattering matrix sM(λ) (Equation (6)) to describe the properties of the metamaterial.
