Optical trapping and alignment of single gold nanorods by using plasmon resonances.
We demonstrate three-dimensional trapping and orientation of individual Au nanorods by using laser light slightly detuned from their longitudinal plasmon mode. Detuning to the long-wavelength side of the resonance allows stable trapping for several minutes, with an exponential dependence of trapping time on laser power (consistent with a Kramer's escape process). Detuning to the short-wavelength side causes repulsion of the rods from the laser focus. Alignment of the long axis of the rods with the trapping laser polarization is observed as a suppression of rotational diffusion about the short axis.
Pelton
Matthew
M
Department of Physics, James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA. pelton@uchicago.edu
Liu
Mingzhao
M
Kim
Hee Y
HY
Smith
Glenna
G
Guyot-Sionnest
Philippe
P
Scherer
Norbert F
NF