Enhanced transmission through subwavelength apertures by excitation of particle localized plasmons and nanojets

TL;DR

This paper demonstrates how plasmonic eigenmodes and nanojets can significantly enhance light transmission through subwavelength apertures, with potential applications in nanophotonics.

Contribution

It reveals the combined effects of particle localized plasmons and nanojets on transmission enhancement in subwavelength slits, supported by numerical simulations.

Findings

Eigenmode excitation leads to transmission enhancement.

Nanojets create highly localized energy in the slit.

Enhancement is universal across materials and particle sizes.

Abstract

We study, and illustrate with numerical calculations, transmission enhancement by subwavelength 2D slits due to the dominant role played by the excitation of the eigenmodes of plasmonic cylinders when they are placed at the aperture entrance; and also due to reinforced and highly localized energy in the slit as a consequence of the formation of a nanojet. We show that, providing the illumination is chosen such that an aperture transmitting eigenmode is generated, the phenomenon is independent of whether or not the slit alone produces extraordinary transmission; although in the former case this enhancement will add to this slit supertransmission. We address several particle sizes, and emphasize the universality of this phenomenon with different materials.