Optical trapping carbon nanotubes

In this study, multi-dimensional manipulations of CNTs bundles including single- and multi-walled carbon nanotubes (SWNTs and MWNTs) with optical trap are performed. By controlling trapping depth, trapping position and polarization of the laser beam, SWNTs and MWNTs bundles with big sizes can be trapped horizontally or vertically, and the vertically trapped MWNTs can be rotated by optical trap while small CNTs can only be trapped collectively. The CNTs bundles with medium length were orientated with the polarization direction of the trapping laser beam in the optical trap. Theoretical calculation based on the interaction between CNTs and laser field shows that the high order nonlinear effect of CNTs in pulsed-laser filed can enhance the trapping force.