Теоретический семинар. Бобылев

Daniel Bobylev

'Nonlocal response of Mie-resonant dielectric particles'

Abstract: Mie-resonant dielectric particles are at the core of modern all-dielectric photonics. In many situations, their response to the external fields is well described by the dipole model, which takes into account only the electric and magnetic dipole moments of the scatterers neglecting the higher-order multipole contributions. In that case, it is commonly assumed that the dipole moments induced by the external fields are given by the product of the particle’s polarizability tensor and the field in the particle’s center. This talk is devoted to the demonstration of nonlocal response of an individual scatterer when the dipole moments of a non-spherical subwavelength dielectric particle are defined not only by the field in the particle’s center but also by the higher-order spatial derivatives of the field thus giving rise to the spatial dispersion which is especially pronounced in the vicinity of anapole minimum in the scattering cross-section. As an illustrative example, we examine the response of high-index dielectric disks applying group-theoretical analysis and retrieving the nonlocal corrections to the dipole response from full-wave numerical simulations. These results provide an important insights into meta-optics of Mie-resonant non-spherical particles as well as metamaterials and metadevices based on them.