Theoretical and experimental study of polarized light scattering by helices

摘要

Abstract: Comparisons are made between a refined model using coupled-dipole theory and the first Born approximation for light scattering from helices. The use of the first Born approximation to model polarized light scattering from a thin wire helix is further developed in order to include all sixteen Mueller scattering matrix elements. (The Mueller matrix fully describes how a structure alters the polarization state of light upon scattering). Comparisons of predicted Mueller matrices between the two theories show that, in some cases, good agreement is obtained. The predicted Mueller matrix for an ensemble of randomly oriented helices using the first Born approximation is calculated. The models based on the first Born approximation and on coupled-dipole theory were also compared to data taken from octopus sperm. We conclude that the first Born approximation may be useful for predicting some elements such as S$-14$/ (the matrix element that describes the depolarization of incident circularly polarized light), but for other elements the coupled-dipole theory is better suited. !42