Optical manipulation of micro-particles with Laguerre-Gaussian mode beam

We have demonstrated an optical trapping and rotation of polystyrene microspheres with a Laguerre Gaussian mode beam. We constructed a Mach-Zehnder interferometer to obtain an interference pattern of Laguerre Gaussian mode and Gaussian mode. A micron-sized objects are trapped in the interference pattern, and by changing the optical path length we could control this pattern to rotate. Since the interference pattern rotates, the trapped particles also rotate.