A New Method to Analyse the Role of Surface Plasmon Polaritons on Dielectric-Metal Interfaces

Abstract

At nano-scale new phenomena have been discovered, allowing devices' miniaturisation, energy harvesting, and power reduction. The Extraordinary Optical Transmission (EOT) phenomenon was reported in 1998 by Ebessen, who stated that the resonant peaks in the response of metallic nano antennas were more intense than predicted by classical diffraction theories. Years later, the main reason for this behaviour was attributed to the Surface Plasmon Polaritons (SPP), at least in ultraviolet and visible regions. In this article, a new method to model the radiation-matter interaction on a dielectric-metal interface is proposed, based on Maxwell's equations and Fresnel Coefficients in absorbing media. Transmission percentage, angle and propagation length are obtained for a rigorous sweep on incident angle and wavelength.The results taken using some noble metals allow us to observe the presence of surface phenomena at expected SPP resonances. First, it is noticeable huge values of transmission in ultraviolet and visible regions, meaning that the metal does not reflect all the radiation. Also, the transmission angle tends to be higher, meaning huge surface components. Furthermore, the transmission length is on orders of 50-100 nm, meaning that phenomena as EOT only occurs at the nano-scale, since waves should arrive at another interface before being absorbed.

A Novel Analysis for Light Patterns in Nano Structures

“…On both cases the complex components of k must be conserved, due to boundary conditions, leading to expression 5 [6], [7]. From this relation it is also determined the relation for the angles ϕ (angle between the incident planes of ê and ĝ), such that ϕ i = ϕ r = ϕ t [1], [2], [6], [7].…”

“…Then, this relation will be valid along all the simulation, since ϕ will be null in every interface [1], [6], [7].…”

“…For example, optical devices such as nano arrays or nanoantennas are commonly used in photonic circuits. The physical principle is based on light-matter interaction [1]- [4]. The classical theories, assuming that metals reflect all incident light, can adequately represent light-metal interaction for radio and microwave frequencies.…”

“…Another interesting aspect is the pattern analysis in comparison with a spectral analysis. Light patterns on a certain target present some important properties that may allow us to design better sensors, detectors or even filters [1], [2], [4]- [6].…”

“…It is a semi-classical approach associated with some wave optics and geometric optics concepts. This methodology was already validated on [1] for a single interface and on [2] for multiple interfaces. The aforementioned patterns, generated by multiple interfaces and complex structures, are compared and validated with electromagnetic profiles.…”