Surface plasmon polaritons in the ultraviolet region

TL;DR

This paper investigates a novel surface plasmon polariton mode confined in nanostructured metal-dielectric interfaces, with wavelengths much smaller than those on flat surfaces, existing in a unique frequency region and observable in materials like aluminum.

Contribution

It introduces a new strongly confined plasmon polariton mode on nanostructured interfaces, expanding the frequency range and material options for plasmonics.

Findings

Mode wavelength is determined by structure period

Propagation length can reach dozens of wavelengths

Exists in frequency region where flat surface SPPs do not

Abstract

We study a surface plasmon polariton mode that is strongly confined in the transverse direction and propagates along a periodically nanostructured metal-dielectric interface. We show that the wavelength of this mode is determined by the period of the structure, and may therefore, be orders of magnitude smaller than the wavelength of a plasmon-polariton propagating along a flat surface. This plasmon polariton exists in the frequency region in which the sum of the real parts of the permittivities of the metal and dielectric is positive, a frequency region in which surface plasmon polaritons do not exist on a flat surface. The propagation length of the new mode can reach a several dozen wavelengths. This mode can be observed in materials that are uncommon in plasmonics, such as aluminum or sodium.