Figure 1

(Color online) Evolution of coupled SPP modal indices in the layered materials with dielectric claddings for $\mid {\epsilon }_m\mid >{\epsilon }_d$ (left) and $\mid {\epsilon }_m\mid <{\epsilon }_d$ (bottom right). System geometries are sketched in top-right inset, where blue (gray) and yellow (light-gray) regions represent dielectric and metal layers. Graphs at the left correspond to $\mathrm{Au}∕\mathrm{Si}{\mathrm{O}}_2$ composite considered in this work; graphs at the right represent its “negative index” counterpart with ${\epsilon }_m=-1+0.1i$ and ${\epsilon }_d={1.444}^2$; $\lambda =1550\mathrm{nm}$. First vertical portion of the figure illustrates the appearance of a SRP-LRP doublet as a result of splitting between two SPPs (left) and as a result of mode-antimode formation (right). Other vertical portions illustrate modal indices in a layered structure when a metal layer is being gradually brought closer to the nanolayer stack.Reuse & Permissions

Figure 2

Field profile (strength of magnetic field versus coordinate across the structure) for a gap plasmon polariton and its modal index and losses as a function of the dielectric layer thickness (left). Profiles of modes supported by a nanoscale multilayer of four silica layers and five gold layers between silica claddings (right).Reuse & Permissions

Figure 3

Effective indices (left) and losses (right) for the modes in silica-gold multilayers. Dashed lines show the limits for the lowest-order and highest-order bulk modes in approximation of infinite number of layers (2).Reuse & Permissions

Figure 4

Experimental reflection data for a silica-gold nanoscale multilayer (circles) and theoretical fit (solid line) indicating ${\mathrm{BPP}}_0$ and ${\mathrm{BPP}}_1$ modes (left). Simulated mode profiles in the experimental structure using the best-fit thicknesses of the layers (right). Solid lines correspond to the structure with high-index silicon substrate. Dashed lines show mode profiles assuming the substrate is silica.Reuse & Permissions