In this work, we present the third order nonlinear optical investigation of two gold complexes, which differ by the nature of the counter cations. The impact of the different design in the architecture through a set of hydrogen bonds in the case of Au-Mel of the systems on the nonlinearity has been studied by means of the Z-scan setup under 532 nm, 30 ps laser excitation, allowing for the determination of the nonlinear absorption and refraction of the samples. Significant modification of the nonlinear optical response between the two metal complexes has been found suggesting a clear effect of the counter cation.

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International audienceThe third nonlinear optical susceptibility (χ〈3〉) of a new family of octupolar molecules with one, two, and three double bonds has been measured at 532 in tetrahydrofuran solutions by the degenerate four-wave mixing (DFWM) method. For comparison, we also measured the analogous dipolar subunits of the molecules. The second hyperpolarizability (γ) for these molecules was deduced. We found that octupolar molecules exhibit large second-order hyperpolarizability (γ) values. The γ  values obtained for octupolar compounds are approximately 10 times larger than those of their corresponding dipolar subunits and 104 times larger than those of CS2, which is a reference material for DFWM

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There is a current interest in research of wide band gap semiconductor materials for the purposes of third order nonlinear optical properties in view of optoelectronics applications. Materials for nonlinear optics should present important changes of nonlinear intensity, dependence on changes of nonlinear refractive index, short response time, and weak absorption losses. We report the results of the third order nonlinear optical susceptibilities of undoped and doped (cerium, fluorine, erbium, aluminum, and tin) zinc oxide films using the third harmonic generation technique at 1064 nm wavelength region in picoseconds regime. Thin films were grown on glass substrate by the spray pyrolysis technique at different temperatures of substrates and characterized by using the x-ray diffraction, scanning electron microscope, transmission, and photoluminescence. A strong third harmonic signal was obtained from the studied films with a good crystallinity and roughness. We have found that at high conductivity, there is a big conversion of the third harmonic signal at different dopants and at an appropriate concentration. We might say that the morphology and the crystalline quality of the films are the main factors for this high conversion.

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