When light interacts with metallic nanoparticles or nanostructures, it can induce collective oscillations of free electrons, known as plasmons. These oscillations can be highly localized near the surface of the nanostructure, creating localized surface plasmon resonances (LSPRs). The resonance conditions are highly sensitive to changes in the local dielectric environment, making LSPRs ideal for sensing applications. By monitoring shifts in the resonance wavelength or intensity, one can detect the presence and concentration of target molecules.
