Application of microscopic models of chirality to second harmonic reflection

Summary form only given. Classical models of chirality are extended to calculate the second-order nonlinear optical response of an isotropic layer of chiral molecules. The one-electron approach and the excitonic coupling model give strikingly different results about the origin of the chiral response in such experiments. Surface second harmonic generation experiments are performed to validate these calculations. They show a good agreement with the theory.We study organic molecules having delocalized electrons to enhance the second order hyperpolarisability. The first one is a polyene with an asymmetric carbon and corresponds to a one-electron chirality. Second harmonic generation is performed with a femtosecond Ti:sapphire laser, in a two-photon resonant configuration.