Electric polarizability of a conductive nanoparticle and its equivalent circuit representation

Dispersion effects and power dissipation by a conductive nanoparticle are revealed by its frequency dependent polarizability, which collectively represents the response of the charge species within the particle to an applied field when the particle diameter is small compared to the wavelength in the embedding medium. Plasmonic interactions in nanoparticles are impetus to a variety of novel device and waveguiding structures realized over frequencies ranging from terahertz to visible optical region. Based on the consideration of the physical process of charge polarization and the frequency dependence of the electric polarizability, equivalent circuits for semiconductor and metal nanoparticles have been developed to facilitate the analysis of aggregates of nanoparticles and composite structures by network theory and effective medium theory.