Analysis of Dual-Band Plasmonic Nanoantenna with Ultra-Thin Circular Gold Layers in Visible Region

Abstract

Aperture-based plasmonic nanoantenna design with dual-band resonance obtained in the region very close to the green wavelength in the spectrum between 400 nm and 700 nm, which can be used in non-invasive biological sensing applications in the future, is presented. In this circular aperture-based nanoantenna design, the effect of changing the material thickness and dielectric medium parameters on the antenna response is investigated. In the nanoantenna design using a double-layer conductive gold layer, both of thickness values are reduced to 5 nm. It is observed that this thickness value exhibits a very strong transmittance response compared to the thicker gold layer values used in the visible region. In this nanoantenna, which exhibits dual band properties at 508 and 551 nm wavelengths, the strongest transmittance peaks are obtained for 5 nm thickness of gold, 100 nm thickness of magnesium fluoride and the 100 nm radius of the circular aperture. In order to contribute to spectroscopic sensing applications, hot spots locations and near field enhancement distribution maps are also examined.