Doubly resonant optical nanoantenna arrays for polarization resolved measurements of surface-enhanced Raman scattering

TL;DR

This paper demonstrates that rhomb-shaped nanoantenna arrays with multiple plasmonic resonances can significantly enhance surface-enhanced Raman scattering signals, especially when resonances are tuned to excitation and emission wavelengths.

Contribution

The study introduces a novel nanoantenna array design supporting multiple resonances, enabling polarization-resolved SERS measurements with improved efficiency.

Findings

Nanoantenna arrays support multiple plasmonic modes.

Resonances can be tuned to excitation and emission wavelengths.

Polarization angle affects SERS signal intensity.

Abstract

We report that rhomb-shaped metal nanoantenna arrays support multiple plasmonic resonances, making them favorable bio-sensing substrates. Besides the two localized plasmonic dipole modes associated with the two principle axes of the rhombi, the sample supports an additional grating-induced surface plasmon polariton resonance. The plasmonic properties of all modes are carefully studied by far-field measurements together with numerical and analytical calculations. The sample is then applied to surface-enhanced Raman scattering measurements. It is shown to be highly efficient since two plasmonic resonances of the structure were simultaneously tuned to coincide with the excitation and the emission wave- length in the SERS experiment. The analysis is completed by measuring the impact of the polarization angle on the SERS signal.