A generic metasurface for the optical pulling of dielectric or plasmonic or chiral Mie objects

In the year 1902, scientists observed a phenomenon occurring at metal interface, known as Wood’s anomaly, which led to the discovery of SPP (Surface Plasmon Polariton). Since then, SPP has received a great deal of attention due to its ability to direct light in the sub-wavelength scale. Their ability to pull objects of various materials, however, has not been thoroughly studied yet. Notably, creating pulling force for different types of particles in a single setup is quite challenging and rare in the literature. In this article, we propose a methodology through which exerting pulling force on spherical dielectric or plasmonic or chiral objects has been made possible within a common diameter range in an on-chip configuration by shining the light from the bottom of a metasurface. In our setup, two SPP waves have been excited by using periodic gratings made of metasurfaces placed on a metal–dielectric interface, which has created such optical pulling forces based on non-paraxial behavior of SPP. Pulling in dielectric object has been enabled due to the induced multipole radiation. The reversal of internal electric field and current density, due to interference field of SPP, has generated the pulling force for the plasmonic object. In contrast, the pulling force on chiral objects has been explained based on the direction of energy flow within the object. These changes occur when the SPP becomes non-paraxial enough for the three objects enabling on-chip object transportation and opening new boundaries for radius-based sorting, which can aid in the analysis of nanoparticle and biomolecules.