Strong Asymmetric Surface Plasmon Polariton Emission by a Dipole Emitter near a Metal Surface

TL;DR

This paper demonstrates that dipole emitters near metal surfaces can produce highly asymmetric surface plasmon polariton radiation patterns, enabling directional control of SPP emission for advanced nanophotonic applications.

Contribution

It reveals how rotating and tilted dipoles near metal interfaces generate asymmetric and unidirectional SPP radiation, expanding control over plasmonic emission.

Findings

Rotating dipoles produce unidirectional SPP emission.

Tilted dipoles cause asymmetric radiation patterns.

Material losses or gains influence emission directionality.

Abstract

We show that the surface plasmon polariton (SPP) radiation patterns of point-dipole emitters in the vicinity of a metal-dielectric interface are generally asymmetric with respect to the location of the emitter. In particular rotating dipoles, which emit elliptically polarized light, produce highly asymmetric SPP radiation fields that include unidirectional emission. Asymmetric SPP radiation patterns also result when a dipole oscillates tilted with respect to the plane of the interface and optical losses or gains are present in the materials. These effects can be used to directionally control SPP emission and absorption, as well as to study emission and scattering processes close to metal-dielectric interfaces. Possible implementations of asymmetrically emitting SPP sources are discussed.