Optical manipulation with planar silicon microring resonators.

We demonstrate optically trapping of microparticles on silicon microring resonators. Once trapped on a microring, a particle can be confined in an optical potential with a depth of 25 k(B)T over the entire microring's circumference. The particles are propelled around the microring at hundreds of micrometers per second, producing periodic revolutions at a few hertz. We anticipate that the increased force and highly accurate positioning obtainable with this system will lead to various nanomanipulation applications.