Sensing biological fluids using Resonating Surface Plasmon Polaritons in the THz range

We study the sensitivity of two different metagrids to the presence of biological fluids on the surface. When a THz beam impinges on each metagrid capped with a dielectric substrate, peaks in transmission related to the onset of high order surface plasmon polaritons appear and allow to estimate the properties of a guest fluid filling the partition volume with a very high sensitivity, comparable with record literature values.