Figure 1

(a) Schematic of the metamaterial and the optical measurements and the scanning electron microscopy image of the nanorods after the removal of the anodized aluminium oxide matrix. (b) Spectra of Au permittivity calculated for different values of parameter $R$ in Eq. (1). (c, d) Extinction spectra measured with $p$-polarized incident light for different angles of incidence with the nanorod assemblies unannealed (c) and annealed at $300°\mathrm{C}$ for 2 hours (d). (e, f) Extinction spectra derived from 3D FEM-based simulations for the ${\epsilon }_{\mathrm{Au}}$ corresponding to $R=5\mathrm{nm}$ (e) and $R=10\mathrm{nm}$ (f).Reuse & Permissions

Figure 2

(a) Effective permittivities (real part) of nanorod metamaterial calculated with local EMT for $R=10\mathrm{nm}$; solid and dashed lines correspond to ${\epsilon }_x$ and ${\epsilon }_{yz}$, respectively; nonlocal corrections are observed near ${\epsilon }_x=0$. (b) Dispersion of the two TM-polarized modes calculated according to numerical simulations (dots) and after Eq. (5) (solid lines); dashed black line corresponds to the main wave described by the local EMT. (c–h) The profiles of the electric field in the unit cell around the nanorod for the upper (c–e) and lower (f–h) branches for $\theta =60°$: (c, f) $\lambda =600\mathrm{nm}$, the “main” mode with uniform field (f) and additional wave with strongly nonuniform field (c) can be clearly distinguished; (d, g) $\lambda =700\mathrm{nm}$, regime of strong mode mixing; the profile of both modes is almost uniform; (e, h) $\lambda =800\mathrm{nm}$, the main (e) and additional (h) waves can be distinguished again.Reuse & Permissions

Figure 3

(a, d) The dependence of dispersion of two TM-polarized modes on material absorption: $R=5\mathrm{nm}$ (a) and $R=10\mathrm{nm}$ (d). The decrease in absorption enhances the mode mixing, signified by the avoided crossing between the dispersion curves. Panels (b) and (e) show the extinction profile of the systems in (a) and (d), respectively. Panels (c) and (f) represent the ratio of amplitudes of the two waves at the exit side (metamaterial-glass interface) of the structures in (a) and (d). “$B$” and “$T$” correspond to the bottom and top modes in (a, d); white lines show the spectral positions of the two extinction maxima.Reuse & Permissions