Philip H. Jones, Onofrio M. Maragò & Giovanni Volpe
Fig. 22.5 — Plasmonic optical tweezers
(a) Excitation scheme for a patterned plasmonic substrate based on the Kretschmann configuration. (b) Optical trapping of 4.8 μm-diameter polystyrene microspheres on a structured plasmonic substrate consisting of 4.8 μm- diameter, 40 nm-thick gold pads on a square array of side 25 μm. (c) Calculation of the optical potential energy for a 200 nm-diameter polystyrene sphere and a 0.45 μm-square gold pad. The arrow indicates the in-plane component of the exciting field wavevector, demonstrating that the potential minimum is in the forward direction from the gold pad.
Figure (a) is adapted from Quidant et al., Opt. Lett. 30, 1009–11. Copyright (2005) The Optical Society.
Figures (b) and (c) are reprinted by permission from Macmillan Publishers Ltd: Righini et al., Nature Phys. 3, 477–80, copyright 2007.