Precise position- and angular-controllable optical trapping and manipulation via a single vortex-pair beam

“Optical trapping and manipulation using laser beams play a key role in many areas including biology, atomic science, and nanofabrication. Here, we propose and experimentally demonstrate the first use of a vortex-pair beam in optical trapping and manipulation. We successfully trap two spherical microparticles simultaneously by a single vortex-pair beam. Precisely position-controllable manipulation of the trapped spherical microparticles is realized by adjusting the off-axis distance of the vortices on the initial phase plane of the vortex-pair beam. Based on the feature of the vortex-pair beam, as an optical wrench, the high-precision angular-controllable rotation of the cylindrical microrod is achieved by rotating the initial phase structure. Our result provides a rich control on the trapping of microparticles and has greatly important applications in biological area, and optically driven micromachines or motors.”