ANALYTICAL DESCRIPTION OF PLASMON REFLECTION FROM THE FREE EDGES OF METAL SLIT STRUCTURES

Abstract

n this paper we consider gap surface plasmon (GSP) propagation properties in slit milled in metal. Developed theoretical model allows to derive equations describing the reflection and transmission of the GSP from the free edge of semi-infinite slit or periodic array of semi-infinite slits in metallic host, analytically. Using these equations we calculate the transmitted power efficiency from the slit and from the array of slits. For the conditions when slit width (d) is very small compared to incident wavelength, the transmitted power efficiency is increased proportional with d^3/2, otherwise the dependence is linear. The relation of transmitted power through periodic array of slits to the transmitted power from single slit depends on slit period for the fixed wavelength. The derived equations give mathematical mechanism to calculate theoretical resonant length, losses and Q-factor of plasmon gap microresonator structures and can be used as a preliminary guideline upon designing plasmon gap microresonator.