Elusive Pure Anapole Excitation in Homogenous Spherical Nanoparticles with Radial Anisotropy

Figure 1

Schematic illustration of anopole excitation in a homogenous particle with plane wave incidence. The radius of the particle is , and the particle is isotropic with refractive index or is radially anisotropic with transverse permittivity and radial permittivity (the anisotropy parameter is expressed as ). Within the particle, both and are excited, out of phase and of the same magnitude with regard to the scattered power. At the same time, the typical current and magnetic field distributions for only have been shown.