Unidirectional Transverse Light Scattering in Notched Silicon Nanosphere

Abstract A nanoantenna that has the capability to direct light to a preferred direction is of paramount importance in a variety of applications in nanophotonics. Directional light scattering by a nanoantenna is achieved by properly controlling the interference between the electric and magnetic multipolar modes. In this work, it is theoretically and experimentally demonstrated that introduction of a small perturbation, i.e., a formation of a notch, to a Mie resonant silicon nanosphere (Si NS) results in the formation of a unique structure exhibiting unidirectional transverse light scattering in the visible range. Based on comprehensive numerical simulations including exact multipole decomposition analyses, the mechanism of the unidirectional transverse scattering is discussed. It is also shown that a notched Si NS can generate a relatively large transverse optical force as the recoil of the unidirectional transverse scattering. Finally, notched Si NSs are fabricated by a solution‐based process. By combining incident‐angle resolved single particle scattering spectroscopy with numerical simulations, directional transverse light scattering of a notched Si NS is confirmed.