Plasmon coupling effect on propagation of surface plasmon polaritons at a continuous metal/dielectric interface

The resonant coupling of surface and bulk plasmons that occurs inside the transition layer between a metal and a dielectric significantly modifies waveguiding properties of metallic nanostructures. In particular, it heavily affects the propagation of the surface plasmon polaritons maintained by a metal/dielectric interface. It is demonstrated that a great part of the energy guided by the surface plasmon polaritons is transmitted through this resonance to the bulk plasmons of the transition layer. The related damping of the surface polaritons is shown to be comparable to, or even higher than, the collisional attenuation. Thus, the plasmon coupling is predicted to play a key role for a range of plasmonic applications based on surface polaritons and their propagation in metallic nanostructures.

Figure 1

Spatial distribution of the complex dielectric permittivity $\varepsilon (x)$ across the continuous Ag/SiO${}_2$ interface. The dashed curve shows the case of the linear profile used in the calculations.

Figure 2

Wavelength ${\lambda }_z$ and propagation distance $L_z$ of the surface plasmon polaritons ($\lambda =800$ nm) on the continuous Ag/SiO${}_2$ interface with the linear profile for the transition layer of the thickness $2d$. The shaded areas depict the forbidden region $2d<1.5$ nm defined by the natural transitions between silver and silicon dioxide.

Figure 3

Distribution of the normalized magnetic $\left|H\right|/\left|H_0\right|$ and electric $\left|E\right|/\left|H_0\right|$ fields of the surface plasmon polaritons across the transition layer with the linear profile for different thicknesses $2d$.

Figure 4

Spatial distribution of the nonlinear dielectric permittivity $\varepsilon (\mu ,x)$ in the transition layer with the linear equilibrium profile and the thickness of 5 nm for different values of the nonlinear parameter $\mu$.

Figure 5

Nonlinear dependence of the wavelength ${\lambda }_z(\mu )$ and the propagation distance $L_z(\mu )$ of the surface plasmon polaritons ($\lambda =800$ nm) for the transition layer with the linear equilibrium profile and the thickness of 5 nm.