Trapping and Rotation of Nanowires Assisted by Surface Plasmons

We report long-range trapping of vanadium dioxide (VO
₂
) and vanadium oxyhydroxide (H
₂
V
₃
O
₈
) nanowires at a distance as large as 50 mum outside the laser spot using plasmonic tweezers and controlled rotation of the nanowires by combining trapping with microfluidic drag force. The plasmonic tweezers are built upon a self-assembled gold nanoparticle array platform. In addition to the long-range trapping and rotation capability, the required optical intensity for the plasmonic tweezers to initiate trapping is much lower (8 muW/mum
²
) than that required by conventional optical tweezers for similar nanowires. We also investigate possible mechanisms for the unique long-range trapping of nanowires through performing control experiments.