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

Abstract

Third-order nonlinear susceptibility ͑3͒ and second-order hyperpolarizability ␥ of poly͕͓3-octylthiophene-2,5-diyl͔-͓p-aminobenzylidenequinomethane͔-bonded multiwalled carbon nanotubes ͑POTABQ-MWNTs͒ were measured in chloroform solution using degenerate four-wave mixing at 532 nm under nanosecond pulse excitation. Effective nonlinear absorption coefficient ␤ eff and nonlinear refraction index n 2 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.

Studies of third-order optical nonlinearities and optical limiting of 2, 3-butanedione dihydrazone

“…The dependence of third-order nonlinear optical properties of BDDH on concentration is investigated in detail. Experimental results are compared with theory, and our results indicate that BDDH exhibit a good optical power-limiting behavior at 532 nm due to reverse saturable absorption (RSA) effect [18][19][20].…”

“…This intensity dependent absorption may include phenomena like two-photon absorption (TPA), ESA, free carrier absorption (FCA), and RSA. The intensity dependent nonlinear absorption of nanosecond pulse at 532 nm can be explained using five-level model [18][19][20] as illustrated in Fig. 8.…”

Measurement of second hyperpolarizability components of a conjugated polymer

“…8,9 The experimental determination of the second hyperpolarizability of the p -conjugated polymers is usually carried out using Z scan and four-wave mixing (FWM) technique. 10,11 Recently, we have proposed a method based on the attenuated-total-reflection (ATR) technique to measure a linear-conjugated polymer's second hyperpolarizability cðÀx 4 ; x 3 ; x 2 ; x 1 Þ in the off-resonance region by assuming that c zzzz is the only non-zero component. 12 However, for many NLO organic materials, the structures of the molecules are so complicated that the second hyperpolarizabilities of the conjugated molecules have more than one non-zero component, and it is essential to measure all the non-zero components to determine the third order nonlinear optical properties of the molecules.…”

Poly(aniline-co-o-toluidine):poly(styrene sulfonic acid) nanocolloidal self assembled multilayer thin films as a hole transport layer in organic solar cells

“…Third generation solar cells based on polymers have attracted much attention of the researchers because of their flexible material processing, strong light absorption, easy formation of hetero interfaces and the high degree of control over the optoelectronic properties [1][2][3][4][5][6][7][8]. Since 1995 the discovery of the bulk heterojunction (BHJ) solar cell has given a great deal of interest in polymer solar cells [9].…”