Plasmonic waveguide-coupled graded nano-rods as nano-optical conveyor belt

We propose a plasmonic nano-optical convey belt for peristaltic transport of nano-particles. Instead of illumination from the top, waveguide-coupled excitation is used for trapping particles more precisely and flexibly. Graded nano-rods with individual dimensions are designed on the waveguide to produce addressable hot-spots coded with different resonant wavelength. Thus, by switching the excitation wavelength sequentially, particles can be transported to adjacent optical traps along the waveguide. Three-dimensional finite-difference time-domain method and Maxwell stress tensor method are used to analyze the feasibility of our proposed design. Simulation results show that this system is capable to excite addressable traps and convey particles in a peristaltic fashion, and the position is well controlled within subwavelength, which provides an alternative design integrating optical manipulation with optical waveguides.