Refractive-index sensing with ultra-thin plasmonic nanotubes

TL;DR

This paper investigates the refractive-index sensing capabilities of ultra-thin plasmonic nanotubes with a dielectric core and metal shell, analyzing the effects of nonlocality and comparing their performance to other sensors.

Contribution

It provides an analytical model for the extinction cross section of nanotubes and evaluates how shape, size, and nonlocal effects influence sensing performance.

Findings

Nanotubes show superior sensitivity compared to other LSPR sensors.

Nonlocal effects significantly influence the sensing properties.

The shape and size of nanotubes affect the figure-of-merit.

Abstract

We study the refractive-index sensing properties of plasmonic nanotubes with a dielectric core and ultra-thin metal shell. The few-nm thin metal shell is described by both the usual Drude model and the nonlocal hydrodynamic model to investigate the effects of nonlocality. We derive an analytical expression for the extinction cross section and show how sensing of the refractive index of the surrounding medium and the figure-of-merit are affected by the shape and size of the nanotubes. Comparison with other localized surface plasmon resonance sensors reveals that the nanotube exhibits superior sensitivity and comparable figure-of-merit.