On the Rayleigh limit of the generalized Lorenz-Mie theory and its formal identification with the dipole theory of forces. II. The transverse case

Optical forces on electric dipoles are usually expressed in terms of the incident electric field components. Gradient forces are then expressed in terms of the electric intensity gradient, while standard and nonstandard scattering forces are found to be physically coupled to contributions associated with both the Poynting vector and an additional term attached to the spin angular momentum of the incident light (spin-curl forces). In this work, we establish a rigorous and formal identification of the Rayleigh limit of the generalized Lorenz-Mie theory with the transverse forces in the Rayleigh limit of the dipole theory, thus complementing a previous work on longitudinal forces and evidencing the origin of spin-curl forces in terms of couplings between beam shape coefficients of distinct order and their relationship with what has recently been called nonstandard scattering forces. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study establishes a connection between the Rayleigh limit of the generalized Lorenz-Mie theory and the transverse forces in the Rayleigh limit of the dipole theory, revealing the origin of spin-curl forces in terms of couplings between beam shape coefficients of distinct order and their relationship with what has recently been called nonstandard scattering forces.