Optical manipulation of micron/submicron sized particles and biomolecules through plasmonics.

Plasmonics, a rapidly emerging subdiscipline of nanophotonics, is aimed at exploiting surface plasmons for important applications, including sensing, waveguiding, and imaging. Parallel to these research efforts, technology yielding enhanced scattering and absorption of localized surface plasmons (LSPs) provides promising routes for trapping and manipulation of micro and nano scale particles, as well as biomolecules with low laser intensity due to high energy conversion efficiency under resonant excitation. In this paper, we show that the LSP-induced scattering field from a self-assembled gold nanoparticle array can be used to sustain trapping of single micron-sized particles with low laser intensity. Moreover, we demonstrate for the first time efficient localized concentration of sub-micron sized particles and DNAs of various sizes through photothermal effect of plasmonics.