Theoretical seminar. Bobylev

11.03.2020
12:00
Begin
11.03.2020
12:00
Place

9 Lomonosov st.

Room 2530

En

Daniel Bobylev

'Nonlocal response of Mie-resonant dielectric particles'

Abstract: Mie-resonant dielectric particles are at the core of modernall-dielectric photonics. In many situations, their response to the externalfields is well described by the dipole model, which takes into account only theelectric and magnetic dipole moments of the scatterers neglecting thehigher-order multipole contributions. In that case, it is commonly assumed thatthe dipole moments induced by the external fields are given by the product ofthe particle’s polarizability tensor and the field in the particle’s center.This talk is devoted to the demonstration of nonlocal response of an individualscatterer when the dipole moments of a non-spherical subwavelength dielectricparticle are defined not only by the field in the particle’s center but also bythe higher-order spatial derivatives of the field thus giving rise to thespatial dispersion which is especially pronounced in the vicinity of anapoleminimum in the scattering cross-section. As an illustrative example, we examinethe response of high-index dielectric disks applying group-theoretical analysisand retrieving the nonlocal corrections to the dipole response from full-wavenumerical simulations. These results provide an important insights intometa-optics of Mie-resonant non-spherical particles as well as metamaterialsand metadevices based on them.