Integral localized approximation in generalized Lorenz–Mie theory

TLDR

Generalized Lorenz–Mie theory describes sphere–beam interactions, but efficient use requires fast evaluation of beam‑shape coefficients, for which the localized approximation offers a less time‑consuming approach. The authors introduce the integral localized approximation to provide a flexible alternative to the standard localized approximation. The integral localized approximation modifies the beam‑shape coefficient evaluation to accommodate changes in the illuminating beam description. The existing localized approximation lacks flexibility when the illuminating beam description is altered.

Abstract

The generalized Lorenz-Mie theory deals with the interaction between spheres and arbitrarily shaped illuminating beams. An efficient use of the theory requires efficient evaluation of the so-called beam-shape coefficients involved in the description of the illuminating beam. A less time-consuming method of evaluation relies on the localized approximation. However, it lacks flexibility when the description of the illuminating beam is modified. We present a new version of this method, called the integral localized approximation, that exhibits the desired property of flexibility.