Plasmonic Nanorod Antenna Array: Analysis in Reflection and Transmission

Abstract

Gold nanorod antenna arrays provide ultrastrong plasmonic field enhancement and a superb broadband spectral tunability, as needed, for example, for label-free biosensing, surface-enhanced Raman spectroscopy, or optical filter design. The key issue when integrating such nanorod substrates is the question whether the plasmonic properties are superior to be applied in reflection or transmission geometry, which clearly needs a thorough analysis. Here we provide a complete and fundamental experimental and theoretical investigation of such gold nanorod antenna arrays embedded in an anodized aluminum oxide matrix. We show that the excitation of individual and coupled plasmonic eigenmodes in such nanorod arrays under an oblique angle of incidence provides an efficient tool for tuning the photonic response for both reflection and transmission applications. Moreover, simultaneous recording of the transmitted and reflected intensities under s- and p-polarization for angles ranging from 0 to 80° over the whole visibl...