Electromagnetic anapole States of nano-disks

Abstract

The possible existence of non-radiating sources is very important for various branches of science from medical imaging to dark matter. Recently, anapole states have been reported as one of the interesting types of non-radiating sources in microwave and optical domains. Many efforts to develop and use them in different aspects such as lasing, metamaterials, sensing and nonlinear optics have been done. Here we numerically study electromagnetic anapole states in high-index dielectric nano-disks. We achieve individual magnetic and electric anapole states in a thin nano-disk. However, the proper optimizing the nano-disk aspect ratio helps to combine the states and obtain a hybrid anapole state at the same wavelength. The Cartesian multipoles decomposition of scattering is done to analyze the structures. It is demonstrated that the scattering of a particle in the hybrid anapole state is much lower than the electric or magnetic anapole states.