Pockels effect in photopolymers derived from ferroelectric liquid crystals

The Pockels effect has been studied in some photopolymers based on chiral smectic C liquid crystals. The materials have different degrees of crosslinking, varying from mesogenic side-chain polymers to anisotropic networks. None of them is switchable but there is an important electrooptic response due to a residual molecular motion at low frequencies. In two of the studied materials, the molecular contribution disappears above several kHz and, in these cases, the electronic electrooptic effect has been fully characterized. The electrooptic coefficients are in the range r=1 pm/V. The actual electronic origin of the measured effect has been confirmed by means of comparison with second-harmonic generation data.