Plasmonic polarization-contrast imaging og aqueous solutions using two-dimensional metallic surface relief gratings

Abstract

Surface plasmon resonance (SPR) microscopy was used for the imaging of inhomogeneous liquid mixtures and surface features. This study is based on the fact that the refractive index changes, resulting from the mixture inhomogeneity or surface imperfections, can be captured with a camera after a polarized light beam passes through a layer of the mixture and the plasmonic interface. Unlike conventional SPR sensing where data is averaged over the sensing area, the SPR microscopy technique produces an intensity variation in the SPR response at each pixel of the image, offering spatial mapping of any given sensing area. We use a technique that enables the removal of the background light entirely and only the SPR converted light can be detected where its intensity is dependent on the local refractive index.