Enhancement of third-order optical nonlinearities by conjugated polymer-bonded carbon nanotubes

Third-order nonlinear susceptibility χ(3) and second-order hyperpolarizability γ of poly{[3-octylthiophene-2,5-diyl]-[p-aminobenzylidenequinomethane]-bonded multiwalled carbon nanotubes (POTABQ-MWNTs) were measured in chloroform solution using degenerate four-wave mixing at 532nm under nanosecond pulse excitation. Effective nonlinear absorption coefficient βeff and nonlinear refraction index n2 were obtained using open aperture and close aperture Z-scan technique at the same wavelength, respectively. Optical limiting property of the sample was also investigated. The resulting POTABQ-MWNTs exhibited large third-order nonlinear optical responses mainly due to the formation of intramolecular photoinduced charge-transfer system of polymers and carbon nanotubes.This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Wei Feng, Wenhui Yi, Hongcai Wu, Masanori Ozaki, and Katsumi Yoshino, J. Appl. Phys. 98, 034301 (2005) and may be found at https://doi.org/10.1063/1.1954887