Figure 4
From: Hyperbolic metamaterials: fundamentals and applications
Dielectric Permittivities. (a) Multilayer system: real part of the dielectric permittivity for an Ag-TiO2 multilayer structure using 35% silver fraction and effective medium theory. (b) Nanowire System: Real part of the dielectric permittivity for an Ag-Al2O3 nanowire structure at 15% silver fill fraction. The Type I and Type II hyperbolic regions of the dispersion and regions of epsilon near zero (ENZ) and epsilon near pole (ENP) are highlighted. The schematic insets in both (a) and (b) show the directions of ENZ and ENP behavior.