Chirality-selective optical scattering force on single-walled carbon nanotubes

We show that optical forces acting on carbon nanotubes are substantially enhanced when the optical wavelength is tuned to resonances in the electronic band structure. Using a tunable laser source, we experimentally demonstrate a resonant optical scattering force on single-walled carbon nanotubes and, by tuning the wavelength, exploit this force to achieve chirality enrichment of four chiralities of nanotubes. Our results represent a significant step towards optical manipulation and sorting of carbon nanotubes based on their chiral vector.