Asymmetrical plasmon distribution in hybrid AuAg hollow/solid coded nanotubes

TL;DR

This study demonstrates the nanoengineering of hybrid AuAg nanotubes with asymmetrical plasmon distributions, revealing distinct localized surface plasmon resonances and high-order modes, enabling advanced control over plasmonic properties for nanophotonic applications.

Contribution

It introduces a novel hybrid AuAg nanotube design with engineered asymmetrical plasmon distribution, combining experimental EELS mapping with BEM simulations for detailed analysis.

Findings

Hybrid nanotubes exhibit coexisting LSPRs from hollow and solid segments.

Asymmetrical plasmon distribution can be modulated and engineered.

High-order modes are disrupted by plasmon hybridization.

Abstract

Morphological control at the nanoscale paves the way to fabricate nanostructures with desired plasmonic properties. We report the nanoengineering of plasmon resonances in 1D hollow nanostructures of two different AuAg nanotubes; completely hollow nanotubes and hybrid nanotubes comprising solid Ag and hollow AuAg segments. Spatially resolved plasmon mapping by electron energy loss spectroscopy (EELS) revealed the presence of high order resonator-like modes and localized surface plasmon resonance (LSPR) modes in both nanotubes. Experimental findings are accurately correlated with boundary element method (BEM) simulations, where both experiments and simulations revealed that the plasmon resonances are intensely present inside the nanotubes due to plasmon hybridization. Based on the experimental and simulated results reported, we show that the novel hybrid AuAg nanotubes possess two significant coexisting features: (i) LSPRs have been generated distinctively from the hollow and solid parts of the hybrid AuAg nanotube, which opens the way to control a broad range of plasmon resonances with one single nanostructure and (ii) the periodicity of the high-order modes are disrupted due to the plasmon hybridization by the interaction of solid and hollow parts, resulting in an asymmetrical plasmon distribution in 1D nanostructures. The asymmetry could be modulated/engineered leading to control coded plasmonic nanotubes.