Nonlinear optical response of C_60 and C_70

Abstract

Second-order hyperpolarizibilities γ of the buckminsterfullerenes C70 at three different wavelengths were determined by third-harmonic generation in a toluene solution and compared with those of C60. Strong effects with γ exceeding 5 × 10−32 esu were observed in the three-photon resonant regime. The nonresonant measurements indicate a negative real hyperpolarizibility in C70 and a positive γ for C60, both of the order of 10−33 esu.