Third-order Nonlinear Optical Properties in New Thiophene-based Extended p-conjugated Systems

I. FUKS- JANCZAREK, A. MIGALSKA-ZALAS, S. DABOS-SEIGNON, B. SAHRAUI, T.J. ZOUEU, I.V. KITYK, J. RONCALI, and C. MARTINEAU

We report measurements of the third-order susceptibilities and twophoton absorption in new C_3h thiophene-based conjugated systems C₆₆H₉₆S₃, C₆₀H₉₀S₃, using degenerate four wave mixing (DFWM) technique at l = 532 nm in the picosecond regime. We have found that increasing number of p-conjugated double bonds leads to an increase of c^<3>. The obtained non linear third-order properties are very large compared to CS₂ which is a reference material for such studies . We show also an increase of the figure of merit with extension of p-conjugation. The obtained result indicates that these novel compounds are promising for photonic applications. In particular due to their important two-photon absorption coefficients these materials could be useful for optical limiting application.