Activity of surface plasmon in the ring-like microcavities

Abstract

ABSTRACT The surface plasmon polariton (SPP) modes fo rmation in the structure consisting from metallic torus and a metallic flat surface separated by dielectric medium, as well as in ring type V-groove cavity ar e considered theoretically. The results obtained for these two structures are compared. The energy of the wave field is mainly concentrated in the dielectric medium at the vicinity of the minimum thickness of the gap between the metallic surfaces. The dependence of the resonant frequency on parameters of the structure was dete rmined. The strongly localized SPP mode in the transverse direction contributes to the increase in th e Purcell factor that is crucial for enha ncement of the spontaneous emission rate. Keywords: Surface Plasmon polariton ˜ Microcavity ˜ Metallic torus ˜ Purcell factor ˜Nanofocusing 1. INTRODUCTION Plasmonic devices offer the combined advantages of ultrafast optical signal processing capabilities of photonics and the potential for sub-wavelength modal confinement, potentially leading to device integration at a scale comparable to electronics. Photonic components utilizi ng surface plasmon polariton (SPP) modes w hose lateral confinement is dictated by the extent of the metal nanostructure (in principle, which can be decreased without cutoff) open the enticing perspective of developing nanometer size optoelectronic circuits operating well below the diffraction limit