Optical levitation of Janus particles within focused cylindrical vector beams

Abstract

The confinement and manipulation of Janus particles have recently garnered significant interest due to their potential applications in fields such as nanotechnology and biophysics, where, under specific circumstances, they can act as microengines and drug carriers. However, the dynamics of Janus particles mostly rely on chemical reactions or thermal gradients, limiting their precision application. To tackle these limitations, we propose the 3D manipulation of Janus particles using focused cylindrical vector beams with a doughnut shaped intensity profile above the focal spot. In particular, we study the behaviour, orientation and manipulation of different highly reflective Janus particles composed of silica or polystyrene with a gold cap in the presence of optical potentials generated by focused cylindrical vector beams. Where the radiation pressure predominantly affects the gold cap rather than the bare particle body of the particle. We demonstrated the potential of the proposed levitation technique for controlling a wide range of Janus particles and real-life complex objects with high reflectivity.