Angular dependence and absorption properties of the anapolemode of Si nano-disks

Abstract: The polarization- and angle- resolved optical response of the anapole mode in silicon nano-disks array have been experimentally and theoretically investigated. The good agreement betweenmeasured data and simulations yields to a consistent description of the anapole mode behaviorthat exhibits different features for TE or TM polarization excitation. Scattering matrix calculationallows us to disentangle scattered and diffused light contributions and to provide a quantitativeestimation of the absorbance enhancement associated to 2D excitation of the anapole mode. Weperformed the multipolar decomposition of the far-field scattered radiation for both TE and TMpolarizations and unambiguously identified the anapole resonant condition in excellent agreementwith the experimental results over a large range of incident angles. Our findings demonstrate thecontrolled excitation of electromagnetic anapole modes in engineered arrays of silicon nano-disksfor the development of optical nanostructures with enhanced light-matter interaction