Third-order nonlinearities in organic polymers and the role of microscopic cascading of second-order hyperpolarizabilities
G. Assanto, D. Neher, G. I. Stegeman, W. E. Torruellas, M. B. Marques, W. H. G. Horstuis, and G. R. Mohlmann
Mol. Cryst. Liq. Cryst. 222, 33-43 (1992)
Abstract:We investigate the third-order nonlinearity of DANS and DAN2 side-chain polymers by tunable third-harmonic generation and nonlinear distributed coupling. The large third-order susceptibility can be interpreted in terms of microscopic cascading of second-order hyperpolarizabilities.