Femtosecond optical Kerr study of heavy-atom effects on the third-order optical non-linearity of thiophene homologues: electronic hyperpolarizability of tellurophene

Second hyperpolarizability γ of tellurophene (C4H4Te), a tellurium-containing homologue of thiophene, was measured by optically heterodyne-detected optical Kerr effect (OHD–OKE) experiments. We found that the γ of tellurophene was +6.3×10−36 esu and was larger than twice of that for selenophene and almost three times that for thiophene. The large γ for tellurophene as the homologue was discussed in terms of the symmetry species of the two lowest excited states and their transition energies from the ground state under the 3-state approximation. Low-lying excited A1 state is presented as the plausible cause of the large γ.