Manipulation of local angular momentum in the tightly focused optical field via the variation of polarization in radial direction

Abstract

The redistribution of angular momentum density can be achieved by tightly focusing the special vector optical fields, which can induce the orbital motion of the microscopic particles. Here, we investigate the focusing properties of radial-variant hybridly polarized vector optical fields with the polarization state varying along the different circular trajectories of the Poincaré sphere. It is found that the redistribution of local angular momentum is induced by the assembling of asymmetric spin flow derived from the orthogonal circularly polarized components of the vector optical field. On this basis, we present an effective method for flexibly manipulating the angular momentum density distribution by customizing the variations of polarization corresponding to different circular trajectories on the Poincaré sphere. These works may promote the applications of vector optical field in optical microfabrication and micro-manipulation.