ABSTRACT
This chapter introduce some fundamentals of plasmonics. Surface plasmons (SPs) are collective oscillations of conduction electrons in a metal surface, which can be excited by an electromagnetic (EM) wave. The splendid optical characteristics of SPs include, but are not limited to, preferential absorption and scattering of light of particular wavelengths, EM field confinement beyond the diffraction limit and local EM field enhancement. The Drude model does not consider interband transitions that contribute to damping and decrease the lifetime of plasmons. For nanoparticles, the electron oscillation is confined in three dimensions, resulting in the so-called localized surface plasmons. For large particles, the retardation effect becomes prominent, which leads to a red shift of the plasmon resonance. The plasmon coupling between adjacent metal nanostructures can largely shift the localized surface plasmon resonances frequencies and generate hugely enhanced EM fields in the nanogaps between the nanostructures. Plasmon-generated hot electrons attract much attention, as they may play important roles in photochemical and photovoltaic processes.
