Plasmonic Brownian ratchet
  Here we present a Brownian ratchet based on plasmonic interactions. By periodically turning on and off a laser beam that illuminates a periodic array of plasmonic nanostructures with broken spatial symmetry, the random thermal motion of a subwavelength dielectric bead is rectified into one direction. By means of the Molecular Dynamics technique we show a statistical directed drift in particle flow. 
Paloma A. Huidobro, Sadao Ota, Xiaodong Yang, Xiaobo Yin, F. J.   Garcia-Vidal, and Xiang Zhang
cond-mat.mes-hall physics.optics