Evidence of ultrafast optical switching behaviour in individual single-walled carbon nanotubes

The ultrafast photophysics of D2O/sodium dodecylbenzene sulfonate surfactant dispersions of single-walled carbon nanotubes enriched in individual tubes (versus tube bundles) were studied by femtosecond pump-probe spectroscopy in the near-IR (NIR) spectral range. Measurements at 920 nm excitation and variable probe wavelengths showed evidence of superimposed transient bleaching as well as induced absorption behaviour. Our results indicate that such nanotube samples manifest ultrafast pump-induced switching of probe transmission with switching times of less than 1 ps under appropriate conditions. Given their high photochemical and photophysical stability these materials may be suitable candidates for the development of ultrafast NIR optical switches and logic gates.