Cascaded contributions to degenerate four-wave mixing in an acentric organic crystal

We show both theoretically and experimentally by degenerate four-wave mixing that the combined processes of optical rectification and the linear electro-optic effect contribute to the large effective third-order susceptibilities 14?3CS2 of the organic salt 4?N,N^?dimethylamino?4??N?-methylstilbazolium toluene?p?sulfonate (DAST).?Furthermore, the knowledge of the cascaded contributions was used to determine absolute values of the third-order susceptibilities as well as their sign.