ABSTRACT

This chapter discusses the single dipole approximation for modeling finite and periodic collections of nanoscatterers. Different expressions for polarizability reported in the literature are summarized, discussed, and tested against a pure numerical method. It is shown that the use of the polarizability, taken from the exact value of the Mie coefficient, provides the best comparison with full-wave results. The chapter considers the modeling of periodic arrays of nanoparticles excited by a plane wave and by a single dipole via the array scanning method (ASM). It shows a good agreement between full-wave numerical techniques and the single dipole approximation when using the Mie polarizability expression of a single nanosphere, which is easy to use and constitutes a better approximation than the quasistatic polarizability and the quasistatic polarizability corrected with the radiation damping term. Quasistatic solutions, including the near-field approximation and the polarizability, were calculated for an infinite chain and a finite 20-sphere chain.