Longitudinal optical fields in light scattering from dielectric spheres and Anderson localization of light

TL;DR

This paper investigates how structured dielectric spheres influence longitudinal optical fields and their potential to facilitate Anderson localization of light in disordered media, highlighting the importance of sphere design.

Contribution

It demonstrates that structured dielectric spheres can reduce longitudinal fields and enhance scattering, offering new pathways for achieving Anderson localization of light.

Findings

Longitudinal field intensity varies nonmonotonously with sphere size.

Hollow spheres exhibit reduced longitudinal fields.

Coated spheres can be optimized for low longitudinal fields and strong scattering.

Abstract

Recent research has shown that coupling between point scatterers in a disordered medium by longitudinal electromagnetic fields is harmful for Anderson localization of light. However, it has been unclear if this feature is generic or specific for point scatterers. The present work demonstrates that the intensity of longitudinal field outside a spherical dielectric scatterer illuminated by monochromatic light exhibits a complicated, nonmonotonous dependence on the scatterer size. Moreover, the intensity is reduced for a hollow sphere, whereas one can adjust the parameters of a coated sphere to obtain a relatively low longitudinal field together with a strong resonant scattering efficiency. Therefore, random arrangements of structured (hollow or coated) spheres may be promising three-dimensional disordered materials for reaching Anderson localization of light.