Design of crossing metallic metasurface arrays based on high sensitivity of gap enhancement and transmittance shift for plasmonic sensing applications

Abstract

We have systematically investigated a general approach to optimize the optical performances of a 2D array of crossing metal nanoparticle (MNP) thin film. These functionalized metasurface MNPs are designed for use as wavelength-selection filters in high-sensitivity infrared spectroscopic plasmonic sensors. The effects of different structural parameters corresponding to the gap-enhancement and bonded transmittance modes on MNP arrays are studied. Two types of sensor configurations based on gold MNP arrays are thoroughly investigated by using the finite element method. The calculated transmittance spectra of the proposed metasurfaces demonstrate near-infrared transmittance dips with a sensitivity range of 120-700 nm RIU-1 in a dielectric constant (ϵ) ranging from 1.0-3.0. We illustrate that it is possible to increase their sensitivity in the detection of chemical and biological substances. The proposed metasurfaces supporting both core-medium sensitivity and bonded-mode resonances are desirable for label-free sensing applications.