Broadband optical limiting with multiwalled carbon nanotubes

Optical limiting effects in multiwalled carbon nanotubes have been observed in the visible and infrared spectral regions with nanosecond laser pulses. The multiwalled carbon nanotubes investigated include those suspended in distilled water and embedded in polymethyl methacrylate films. Among all the samples measured, the limiting performance of the carbon nanotube suspension is the best with the limiting threshold determined to be $\text{∼1,}$ 5, and $\text{13\hspace{0.17em}}{\mathrm{J/cm}}^{\mathrm{2}}$ at 532, 700, and 1064 nm, respectively. The possible mechanism for the observed effects is discussed.