Fig. 1.

(a) Schematic drawing of the enhanced optical trapping utilizing 1-D periodic nanostructures. The incident beam is diffracted by the periodic nanostructure at far field. (b) The intensity distribution of light with two orthogonal polarizations at the surface of an aluminum grating with a 417 nm period obtained using FDTD simulations. The distribution is normalized to the intensity on a flat aluminum surface. (c) and (d) Trapping potential for particles directly above the grating surface versus location of the particle for (c) a 350 nm polystyrene bead and (d) a 1 μm polystyrene bead. The white circles illustrate the sizes of the particles. Insets show the trapping potential above a flat aluminum surface for the same particle size as comparisons. The values are normalized for each particle size. For all FDTD simulation figures the field of view is 10 × 8 μm².