Three-dimensional optical trapping and manipulation of single silver nanowires.

We report the first experimental realization of all-optical trapping and manipulation of plasmonic nanowires in three dimensions. The optical beam used for trapping is the Fourier transform of a linearly polarized Bessel beam (termed FT-Bessel). The extended depth of focus of this beam enables the use of a retroreflection geometry to cancel radiation pressure in the beam propagation direction, making it possible to trap highly scattering and absorbing silver nanowires.

Controlling the position and orientation of single silver nanowires on a surface using structured optical fields.

We demonstrate controlled trapping and manipulation of single silver (Ag) nanowires in two dimensions at a surface using structured light fields generated with a spatial light modulator. The Ag nanowires are attracted toward the regions of maximal optical intensity along the surface when the trapping laser light is linearly polarized and are repelled toward the minima of optical intensity when the light is circularly polarized. For linearly polarized light, stably trapped nanowires are oriented perpendicular to the polarization direction due to a torque induced by an asymmetrical response of the nanowire to the electric field.

Plasmon-driven selective deposition of au bipyramidal nanoparticles.

We demonstrate the plasmon-selective and driven deposition of (bipyramidal) Au nanoparticles on transparent substrates (glass coverslips) utilizing total internal reflection (TIR) illumination. Near-IR laser light undergoing TIR at a glass-water interface causes colloidal Au bipyramids to irreversibly deposit onto the glass surface. We demonstrate that the deposition process has particle (i.

All-optical patterning of Au nanoparticles on surfaces using optical traps.

The fabrication of nanoscale devices would be greatly enhanced by "nanomanipulators" that can position single and few objects rapidly with nanometer precision and without mechanical damage. Here, we demonstrate the feasibility and precision of an optical laser tweezer, or optical trap, approach to place single gold (Au) nanoparticles on surfaces with high precision (approximately 100 nm standard deviation). The error in the deposition process is rather small but is determined to be larger than the thermal fluctuations of single nanoparticles within the optical trap.

Plasmonic interactions and optical forces between au bipyramidal nanoparticle dimers.

Interparticle forces that can be driven by applied (optical) fields could lead to the formation of new particle arrangements when assembled in arrays. Furthermore, the potentially large interactions and large local fields associated with plasmon excitations in anisotropic nanoparticles can lead to enhanced nonlinear responses and applications for sensing. These and other applications would benefit from simulations of spectra and forces arising from plasmonic interactions.