Manipulating gradient forces on optical tweezers using bessel beams

In this paper, we show how one can change the stable equilibrium of a particle trapped into by optical tweezers through the intensity variation of superposed Bessel beams with different orders. The gradient forces acting on particles of different radii are determined, and the theoretical results indicate that it is possible to combine Bessel beams in such a way that a particle can be manipulated into or out the centre of the beam by exploiting their ring-shaped intensity patterns, without any mechanical displacement of the lasers.