Mesoionic rings as third-order non-linear optical materials

A study of the non-linear refractive index (n2) and the non-linear absorption coefficient (α2) of molecules containing mesoionic rings in solution has been carried out using the Z-scan technique with 70 ps at 532 nm. The second molecular hyperpolarizabilities, γ, were inferred and the experimental results are in a good qualitative agreement with our semi-empirical 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 promising materials for photonic applications.