Pulse duration and wavelength effects on the optical limiting behavior of carbon nanotube suspensions

We investigate pulse duration and wavelength effects on the optical limitin g behavior of single-wall carbon nanotubes suspended either in chloroform o r in water. The principal optical limiting effect in carbon nanotube suspen sions is nonlinear scattering that is due to heat transfer from particles t o solvent, leading to solvent-bubble formation and to sublimation of carbon nanotubes. We report on nonlinear transmittance measurements for pulse dur ations ranging from 3 to 100 ns and for wavelengths from 430 to 1064 nm. Th e dependence of optical limiting behavior on pulse duration and wavelength is analyzed and discussed in terms of nonlinear mechanisms. (C) 2001 Optica l Society of America OCIS codes: 190.3970, 190.4400, 190.4870, 290.5850.