Mesoionic rings as third-order non-linear optical materials

A study of the non-linear refractive index (n(2)) and the non-linear absorp tion coefficient(alpha(2)) of molecules containing mesoionic rings in solut ion has been carried out using the Z-scan technique with 70 ps at 532 nm. T he second molecular hyperpolarizabilities, gamma, were inferred and the exp erimental results are in a good qualitative agreement with our semi-empiric al AM1-TDHF calculations. Optical Kerr gate measurements with 60 fs pulses at 800 nm allowed us to identify an ultra-fast response time for the third- order non-linearity. These results indicate that mesoionic rings are promis ing materials for photonic applications. (C) 1999 Elsevier Science B.V. All rights reserved.