Coaxial nanowires as plasmon-mediated remote nanosensors

TL;DR

This paper demonstrates a novel coaxial nanowire design that enables remote Raman sensing via plasmon propagation, with potential applications in detecting photo-degradable substances and integrated photonic systems.

Contribution

It introduces a new coaxial nanowire architecture for remote Raman sensing, combining gold cores and polymer shells with controlled placement along the nanowire.

Findings

Successful fabrication of coaxial nanowires with controlled polymer shell placement.

Correlation of electron microscopy and Raman spectroscopy confirms nanowire structure.

Proof-of-concept demonstration of remote Raman sensing using the nanowires.

Abstract

This study reports on the plasmon-mediated remote Raman sensing promoted by specially designed coaxial nanowires. This unusual geometry for Raman study is based on the separation, by several micrometres, of the excitation laser spot, on one tip of the nanowire, and the Raman detection at the other tip. The very weak efficiency of Raman emission makes it challenging in a remote configuration. For the proof-of-concept, we designed coaxial nanowires consisting in a gold core to propagate the surface plasmon polaritons and a Raman-emitting shell of poly(3,4-ethylene-dioxythiophene). The success of the fabrication was demonstrated by correlating, for the same single nanowire, a morphological analysis by electron microscopy and Raman spectroscopy analysis. Importantly for probing remote-Raman effect, the original hard template-based process allows to control the location of the polymer shell all along the nanowire, or only close to one or the two nanowire tips. Such all-in-one single nanowires could have applications in the remote detection of photo-degradable substances and for exploring 1D nanosources for integrated photonic and plasmonic systems.