Polarization‐Dependent Optical Forces Arising from Fano Interference

Abstract A Fano resonance originates from the resonant coupling between interacting multipoles inside nanostructures. It breaks the symmetry of spectral line shape and enables Fano‐resonant media to present unusual scattering properties. However, understanding the mechanical effects of such multipolar coupling systems is highly complex compared with the traditional simple dipole. In this work, using single Si nanospheres as the Fano‐resonant media, optical forces arising from different types of Fano resonances including the electric, magnetic, and magnetoelectric Fano resonances are investigated. It is shown that the directions of these types of forces are tunable in three dimensions. The necessary condition to realize a direction change of the Fano‐resonance‐induced forces and elucidate the underlying physics are presented. Furthermore, it is found that the Fano‐resonance‐induced forces exhibit strong polarization‐dependent properties which traditional optical (dipolar) forces cannot possess.