Metal nanowire arrays with ultralow or negative effective permittivity for adsorption-based chemical sensing

Abstract

We investigated wire-mesh media with plasma-like dispersion of dielectric permittivity as a potential medium for nanoplasmonic sensors utilizing adsorption of chemical, biochemical or biological analytes. Such structures belong to the ultra-low refractive index metamaterials and are typically used as one of the building blocks for zero- or negative in ex metamaterials. We analyzed a 2D array or conductive arrays with either a monomolecular/monatornic adlayer on the wire surface or fully immersed into analyte. We calculated the spectra reflection dip caused by the tuning of the effective electromagnetic properties of the wire mesh structure due to the adsorption of the analyte. We investigated the influence of various wire mesh media parameters, including conductivity, mesh geometry, etc., but also of the adsorbed analyte itself (effective optical properties, adlayer thickness). We considered the applicability of the structure in a reflection-based readout scheme without any special configurations for signal extraction.