A comparative theoretical study of higher harmonic generation and electro-optic effects in polyene systems

Abstract

Second- and third-order dynamic polarizabilities related to the Pockels and Kerr coefficients of polyenes and substituted polyenes have been computed exactly for a Pariser-Parr-Pople model. It is found that at any given frequency away from resonance the susceptibility relating to the Pockels effect is larger than the second-harmonic-generation (SHG) coefficient and that corresponding to the Kerr effect is larger than either the electric-field-induced SHG or the third harmonic generation coefficients, although the size dependence is governed by the order of nonlinearity. The Pockels coefficient, unlike the Kerr coefficient, is sensitive to the push-pull strength.