Controllable optically induced rotation based on rotationally-symmetric power-exponent-phase vortex beams with high-efficiency

This paper presented and demonstrated an efficient and controllable method for optically induced rotation by utilizing rotationally-symmetric power-exponent-phase vortex beams (RPVBs). Based on the Richards-Wolf vector diffraction integral formula and the Poynting vector theory, the orbital angular momentum distribution of the tightly-focused RPVBs was analyzed to reveal the optimal values of topological charge l and power index n of the RPVBs for driving the rotation of microparticles. Then, the experimental setup of the optical tweezer was established to verify that the optically induced rotation of multiple particles can be achieved by applying the RPVBs, of which the rotation velocity is not only dependent on the topological chargel, but also related to the power index n . Thus, the controllable optically induced rotation with different rotation speed can be obtained by modulating both the topological charge and power index. The optimal values for achieving the maximum rotation speed show that, compared with the vortex beams, the RPVBs can enable the particles to rotate with low power threshold, and accelerate the particles rotation, due to the strong intensity gradient, which highlights the efficiency of RPVBs in optically induced rotation. These findings offer a more flexible and efficient option for optically induced rotation in biomedicine, atomic physics, nanotechnology, and so on.