Nonlinear optical properties of hydroxyl groups modified multi-walled carbon nanotubes

Nonlinear optical properties of hydroxyl groups modified multi-walled carbon nanotubes (MWNTs-OH) with diameter of 20–30 nm (MWNTs 2030 -OH) dispersed in water, N , N -dimethylformamide (DMF) and chloroform were studied by using Open-aperture Z-scan technique with nanosecond pulse at 532 nm. The influences of solvent, laser pulse-width, on-axis fluence at focus and concentration on nonlinear optical properties of MWNTs 2030 -OH were analyzed in detail to obtain the optimal nonlinear optical response for applications in optical limiters. Nonlinear optical properties of MWNTs-OH with different diameter in DMF were also studied and compared with multi-walled carbon nanotubes in DMF and C 60 in toluene.