Self-diffraction and high nonlinear optical properties of carbon nanotubes under CW and pulsed laser illumination

In this work, self-diffraction effect in carbon nanotubes (CNTs) that were dispersed on N,N-dimethylformamide (DMF) solvent is studied. Third-order nonlinear optical coefficients of this nano-suspension are measured using z-scan technique and high nonlinearity is observed. Nonlinear refraction index of the order −10−6cm2W is obtained due to the thermal effect and the nonlinear interaction of the light and the surface plasmonic electrons. Optical diffraction rings of the sample under He-Ne laser illumination at a wavelength of 632.8 nm were observed and intensity distribution of the rings is explored. At last, optical limiting performance of CNTs is investigated under irradiation by a continuous wave (CW) He-Ne laser. The optical limiting behavior is investigated by using transmission measurement through the sample and our studies indicate that this material is a potential candidate for optical limiting applications in low power CW regime.