Second order hyperpolarisabilities of various series of organic compounds:Tetrathiafulvalene derivatives

We have measured the third-order susceptibilities chi ((3))(ijkl) of a few series of tetratiafulvalene derivatives using the degenerate four wave mixi ng method. From these measurements we have deduced the values of the second -order hyperpolarisabilities gamma and their corresponding molecular and el ectronic contributions. We compare the third-order optical properties of th ese new extended tetrathiafulvalene derivatives with the properties of othe r analogues of TTF. we have studied previously. All organic molecules studi ed in present work reveal large second-order non-linear optical hyperpolari sability.