Surface plasmon dynamics of a metallic nano-particle

The paper presents a theoretical framework to explain the surface plasmon dynamics in a single metallic nano-particle (MNP). The plasmon physical mechanisms, i.e, internal oscillation energy, electromagnetic near-field energy and power-flow are analyzed here in terms of electric dipole moment of a single metallic nano-particle. The resonant mode shift and hybridization of a metallic nano-shell with annular metallic region are also calculated on the basis of internal oscillation energy and electrostatic approximation. The paper also calculates the power-flow due to relaxation, radiation, plasmon-coupling in the surrounding matrix, and applied electromagnetic (EM) signal. The law of conservation of energy is used to compute the relaxation damping, radiation damping, and surrounding matrix coupling effect. Finally, the resonant behavior of a single metallic nano-particle is represented by a lumped resonant circuit model. The lumped circuit parameters are determined by deriving the equation of motion of electric dipole moment and the electromagnetic near-field energy outside the metallic nano-particle.