Gradient Force Evolution through a Piecewise Cylindrical Vector Beam

Optical gradient force plays an important role in optical tweezers, which accelerated many advances in life science. The optical gradient force patterns in focal region of a concentric piecewise cylindrical vector beam is investigated theoretically in this paper. Numerical results show that the evolution of the optical force pattern can be adjusted considerably by changing the radius and polarization rotation angle of each portion of the vector beam. And some interesting trap patterns may occur, such as cup shell shape trap with one trap at its each side along axis, rectangle shell shape trap with one trap at its each side, dumbbell optical trap, spherical shell optical trap, which shows that the concentric piecewise cylindrical vector beam can be used construct controllable optical tweezers.