3D Nanoporous Antennas for high sensitivity IR plasmonic sensing

TL;DR

This paper demonstrates that 3D nanoporous gold antennas significantly enhance infrared plasmonic sensing sensitivity due to superior field confinement, outperforming bulk metal structures in detecting environmental changes and biosensing applications.

Contribution

It introduces the use of nanoporous gold as a high-sensitivity IR plasmonic sensor platform, showing improved performance over bulk metals through experimental comparison.

Findings

Nanoporous gold exhibits higher field confinement in IR compared to bulk metal.

Sensors made of nanoporous gold achieve sensitivities over 4,000 nm/RIU.

Biosensing of peptides confirms enhanced sensitivity due to nanoporous structure.

Abstract

Nanoporous gold can be exploited as plasmonic material for enhanced spectroscopy both in the visible and in the near infrared spectral regions. In particular, with respect to bulk metal it presents interesting optical properties in the infrared where it presents a significantly higher field confinement with respect to conventional materials. This latter can be exploited to achieve extremely high sensitivity to the environment conditions, hence realizing interesting sensors. Here we compare the sensitivity of a plasmonic resonators made of nanoporous gold with a similar structures made of bulk metal. The experimental test of the enhanced sensitivity was performed by depositing the same stoichiometric quantity of dielectric material onto the two considered structures. The result, also confirmed by the biosensing of a short peptide, can be ascribed to the better field confinement and enhancement in porous metal. This suggests an application of nanoporous 3D structures as sensor platform in the near-infrared with sensitivity over 4.000 nm/RIU.