ANGULAR MOMENTUM DENSITY OF SURFACE PLASMON POLARITON ENHANCED ELECTROMAGNETIC FIELDS EXCITED BY TIGHTLY FOCUSED STATISTICAL BEAMS

Abstract

Our work in plasmonics is concerned with coherence properties of partially coherent, twisted Gaussian-Schell model (TGSM) beams tightly focused on a thin metal film. We have simulated the spectral density of in-coupled light and shown that it is strongly affected by the surface plasmon polariton (SPP) generation. This also confirms our original assumption that strong SPP coupling can be realized in this configuration. The calculation of the angular momentum density shows that its distribution can be controlled by the beam coherence length and a twist parameter magnitude. The sharp angular momentum density maxima and their distribution tend to be smeared out as the coherence length decreases. In addition, the axial component of angular momentum distribution becomes delocalized as the strength of phase twist of an incident beam is increased.