Transversal energy flow of tightly focused off-axis circular polarized vortex beams

Abstract

The transversal energy flow characteristics of tightly focused circular polarized beams carrying off-axis vortices are examined in this research work. The results reveal that the symmetry of the focal fields are destroyed and energy flow is offset by the existence of off-axis vortices. Therefore, the focal field and energy flow distribution of polygons (bar-type-like, triangle-like, and square-like) can be realized by the superposition of multiple off-axis vortices with controllable positions. Furthermore, based on off-axis vortex energy flow characteristics, the force exerted on the metal particles in polygon focal fields is found to rotate the particles clockwise along the outlines of the polygon energy flow. The results will potentially provide new ideas and theoretical guidance to explore focal field and particle control methods.