Explanation of Optical Force and Torque on Nanomotors as the Interplay of Huygens Sources

Being able to understand how optical forces emerge from the interaction of light with matter is paramount for controlling the motion of nanoparticles as well as powering nanomotors. The purpose of this work is to uncover the physical mechanisms at the origin of these forces and show how they can be engineered. We demonstrate that the interplay between symmetric and asymmetric multipolar modes in a Kerker-like fashion is responsible for asymmetric scattering, which results in a time-average non-zero optical force and possibly optical torque.