Nonlinear optical properties of asymmetric polyphenyls: Efficiency versus transparency trade-off

Abstract

First-order hyperpolarizabilities β of a sequence of dimethylaminocyanopolyphenyl oligomers are measured by using the electricfield induced second harmonic generation technique. High β values (up to 55 × 10 −30 esu at zero frequency) are reported to be in-keeping with transparency in the visible and near UV spectral range. The behaviour of β related to the number of phenyl units is compared to calculated hyperpolarizabilities and discussed in terms of trade-off between intramolecular charge transfer and the non-coplanarity between the benzene rings.