Interfering surface and localized plasmon: Tuning the Wood anomaly for biosensing

We demonstrate spectra of slabs of plasmonic 1D nanostructures and show their changes when detecting specific biomolecular binding. The slabs were fabricated by electron-beam lithography, they had sub-millimeter dimensions and allowed us to detect a specific binding of low-density lipoproteins. Optical spectra of the slabs exhibiting a spectrally sharp resonant peak have been analyzed numerically to interpret their features and to define structural parameters governing the quality factor of the resonance. We show a comparison between the sensing performances of the different slabs under study, thus discussing their better designs and experimental geometries.