Surface Plasmon-Based Manipulation of Microparticles and Dynamics Study

Open Access
Yan, Wei
Graduate Program:
Engineering Science
Master of Science
Document Type:
Master Thesis
Date of Defense:
July 18, 2008
Committee Members:
  • Jun Huang, Thesis Advisor
  • surface plasmon tweezers evanescent field manipula
The manipulation of micrometer or nanometer scale objects based on light-matter interaction has been a hot topic ever since Ashkin proposed in 1986 the ¡°optical tweezers¡±, which realized optical trapping and manipulation of polystyrene latex micro-particles through focused laser beams. Notably, Kawata et al. manipulated micrometer scale spheres near the surface of a prism based on radiation pressure generated by total internal reflection-induced evanescent field. Righini et al. introduced ¡°surface plasmon tweezers¡± by trapping single microparticles on patterned gold structures under surface plasmon excitation. There remains much work to be done, however, in areas including patterning techniques and dynamics study of manipulated objects. The disclosed thesis contributes to the breadth of knowledge on optical manipulation. Key developments in the field were first reviewed. From this background ¡®surface plasmon tweezers¡¯ were devised to trap and arrange polystyrene beads. The aggregation of the beads was driven by the combination of force and thermal gradient, and the bulk migration of said beads by radiation pressure or scattering force along the light propagation direction. The dynamics of the beads were also found to be subject to thermal convection. Lastly, a tunable, surface plasmon-based patterning technique was proposed.