On a relationship between acoustical (more generally scalar) beam shape coefficients and electromagnetic beam shape coefficients of some T-matrix theories for structured beams

Abstract

On one hand, we consider two T-matrix theories, namely “Generalized Lorenz–Mie theory” (GLMT) and “Extended Boundary Condition Method” (EBCM), in which structured beams may be expanded over Vector Spherical Wave Functions (VSWFs), with expansion coefficients expressed by using electromagnetic Beam Shape Coefficients (BSCs). On the other hand, we consider acoustical (more generally scalar) fields which may be expressed similarly by an expansion over basic functions, with expansion coefficients expressed using acoustical (scalar) BSCs. We establish relationships between electromagnetic and scalar BSCs.