plasmonresonans
Plasmonresonans, often written plasmon resonance, is the resonant oscillation of free conduction electrons at the interface between a metal and a dielectric when driven by light. In nanostructures this gives rise to localized surface plasmon resonances (LSPR) in nanoparticles and surface plasmon polaritons (SPP) on extended metal–dielectric surfaces. These resonances lead to strong optical absorption and scattering at specific wavelengths and to enhanced local electromagnetic fields.
In noble metals like gold and silver, conduction electrons collectively oscillate when the incident light frequency
Resonance positions shift with particle size and shape, material, and the refractive index of the surrounding
Applications include biosensing and chemical sensing through refractive index changes, colorimetric assays based on plasmon coupling,
History and theory: early observations of anomalous coloration in colloidal metals led to the concept; Mie