Electronic and nuclear contributions to the third-order nonlinear optical properties of new polyfluroalkysulfanyl-substituted tetrathiafulvalene derivatives

Abstract From DFWM efficiency measurements, we deduce third-order susceptibility of polyfluroalkylsulfanyl-substituted TTF derivatives. To know the physical nature of the optical non-linearities, we separate the electronic and nuclear contributions in χ 〈3〉 . The electronic contribution of these molecules turned out dominant. We also deduce the values of the second-order hyperpolarisabilities γ which are about 10 3 greater than the γ value of CS 2 at the same wavelength 532 nm As the absorption of the studied compounds is very weak at 532 nm, their merit factors in term of relation between the third-order susceptibility and linear absorption coefficient are better than the ones obtained for ethylenic TTF derivatives studied previously.