Abstract: The disclosure relates to a substrate comprising a micro- or nanostructured periodic array comprised of a plurality of anisotropic metallic micro- or nanostructures, wherein each of the plurality of nanostructures induce an average maximum and substantially uniform plasmonic field greater than 108 across the substrate; a plurality of Raman-active linker molecules directly bound to the metallic micro- or nanostructures; and a plurality of capture molecules directly bound to the Raman-active linker molecules. The disclosure also relates to systems, devices, and methods that use the substrates to determine the concentration of various analytes.