Femtosecond laser converts metallic to semiconducting carbon nanotube

A novel method for fast and accurate local tuning of the optoelectronic properties of single-walled carbon nanotubes makes use of ultrafast-pulsed lasers. The method is based on localized two-photon oxidation of carbon nanotubes when the laser irradiates with energies far below the ablation threshold. At such low energies the nonlinear photochemical interaction of femtosecond laser and carbon atomic lattice prevent thermal effects.