Designing Plasmonic Sensors Using Babinet's Principle

Localised surface plasmons excited on nano-/microstructures acting as plasmonic nanoantennas [1]–[3] have attracted increased attention in recent years with their ability to strongly confine incident electromagnetic (EM) fields in the visible and near-infrared regime. LSP resonances excited on plasmonic structures have been shown to strongly enhance incident fields with subwavelength spatial resolutions close to their surface (the near field) [4]–[10]. Sensors have also benefited from research and innovation in plasmonics. This is due to the spectral position of LSP resonances being sensitive in plasmonic nanostructures to external changes such as variations in the thickness and refractive index of a nearby dielectric.