Efficient Confinement of Ultraviolet Light into the Self-Assembled, Dielectric Colloidal Monolayer on a Flat Aluminum Film

TL;DR

This paper demonstrates a method to efficiently confine UV light into a hybrid plasmonic-photonic crystal made by self-assembling dielectric nanospheres on aluminum, achieving higher quality factors and tunability for enhanced UV light interaction.

Contribution

It introduces a novel self-assembled dielectric colloidal monolayer on aluminum for UV light confinement, with tunable resonant modes and significantly improved quality factors over existing nanostructures.

Findings

Higher Q-factor (at least ten times) than existing Al nanostructures.

Resonant modes tunable from deep to far UV by adjusting nanosphere size.

Native oxide effects on SPP and WG modes analyzed for fabrication guidance.

Abstract

Here we propose the efficient confinement of ultraviolet (UV) light into the plasmonic-photonic crystal hybrid, which can be practically developed by the self-assembly of dielectric colloidal nanosphere monolayer onto a flat aluminum (Al) film. Using a numerical approach, we analyzed modal characteristics of each different resonant mode at the UV wavelengths including surface plasmon polariton (SPP) mode and waveguided (WG) mode and tuned these resonant modes from deep to far UV simply by adjusting the size of dielectric colloidal nanosphere. The calculated quality-factor (Q-factor) of such plasmonic-photonic crystal hybrid is at least one order of magnitude higher than that of the existing Al nanostructures (Al nanoparticles, nanodisks, nanovoids, or nanogratings) standing on the dielectric substrate. Also, we systematically studied how the amount of native oxide, which can be generated during the general process for the deposition of Al, can influence on both the SPP and WG modes of such plasmonic-photonic crystal hybrid in order to guide strategies for a realistic experimental fabrication and exploitation of relevant optical responses. We anticipate that the theoretical results in this paper enable a promising step in the enhancement of UV light interaction with the nanophotonic structure in a versatile, but highly efficient way.