Scattering of Light from Two Interacting Spherical Particles

Abstract

Linear optical properties of two spherical particles interacting via their dipole fields are studied. The dipole susceptibility and cross-sections of extinction, scattering and dissipation are found as functions of susceptibility χ₀ of an isolated particle. The case of arbitrary distance between particles is considered (which include interaction in near-zone, transitional-zone and far-zone). It is shown, that radiative energy losses of an oscillating dipole give rise to a finite phase shift between oscillations of the dipole and it's electromagnetic field in the near-zone. Application of this fact to the problem of two interacting dipoles leads to appearance of two additional resonances of susceptibility of the pair with radiative half-width tending to be zero when r₁₂→0 as (r₁₂/λ)², where r ₁₂ is the distance between particles.