Rational Design and Optimization of Plasmonic Nanohole Arrays for Sensing Applications

Abstract

The design and optimization of plasmonic nanohole arrays (NHAs) as transducers for efficient bioanalytical sensing is a rapidly growing field of research. In this work, we present a rational method for tailoring the optical and functional properties of Au NHAs realized on planar transparent substrates. Experimental and numerical results demonstrate how the far- and near-field properties of the NHAs can be controlled and optimized for specific sensing applications, proving a valuable insight into the distribution of electric fields generated on the nanostructured metal surface and the depth of penetration into the surrounding media. Metal thickness is found to play a crucial role in determining the sensing volume, while the diameter of the nanoholes affects the localization of the electromagnetic field and the extent of the decay field. The remarkable surface and bulk refractive index sensitivities observed a rival performance of more complex geometric designs reported in the recent literature, showcasing their outstanding potential for chemo-biosensing applications.