Characterization of Transport and Trapping Behavior of Nanoparticles in a Simple Square Nanoscale Plasmonic Optical Lattice

Ya-Tang Yang Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan Chia-Chun Hung Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan Tsang-Po Yang Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan Jer-Shing Huang Chemistry, National Tsing Hua University, Hsinchu, Taiwan

Recent advances in optical tweezer technique have made it an ideal tool to create one, two, and three dimensional periodic optical potential.[1] Such periodic potentials have found interesting technological and fundamental applications such as particle sorting and optical matter crystallization. Shrinking of these experiments into the nanoscale is difficult because far-field based traditional optical tweezer techniques is limited by diffraction. To overcome these diffraction limits, researchers have developed near-field optical trapping techniques using metallic plasmonic nanostructures.[2] Previously, our group has reported first long range matter organization and transport behavior of nano particles in a two dimensional plasmonics enhanced optical lattice.[3] Here we report the characterization of transport and trapping behavior of nanoparticles for a plasmon-enhanced two dimensional, polarization-dependent, simple square optical lattice. The optical potential is created by illuminating an array of gold nanodisks with a loosely focused Gaussian beam to excite plasmon resonance. We show that nanoparticles can be guided and arranged by such an optical potential. Enhanced drift velocity as compared to free diffusion rate is also reported. We observe the transport of (both single and multiple) nanoparticles over such an optical lattice. Thermal convection force due to heating in plasmonic nanostructures will also be discussed. Integration with such optical lattice with microfluidics will also enable the study of stochastic transport and applications such as nano particle optical sorting.

yatang32@gmail.com

Schematic of the experiment and particle trajectory

  1. D. A. Grier Nature, 424, 810 (2003).
  2. M. L. Juan, R. Gordon, Y. Pang, F. Eftekhari, and R. Quidant Nat. Photonics, 5, 915 (2009).
  3. K. Y. Chen, A. T. Lee, C. C. Hung, J. S. Huang, and Y. T. Yang, Nano Letter, 13, 4118, (2013).








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