Langevin Type Alignment in a Smectic Liquid Crystal Mixture Showing V-Shaped Switching As Studied by Optical Second-Harmonic Generation

Abstract

Second-harmonic generation (SHG) was observed in a homogeneously aligned smectic C * -like liquid crystal (LC) cell showing V-shaped switching during the application of a triangular wave. At normal incidence of light, abnormally strong SHG signals were observed at about zero electric field. It was confirmed that this phenomenon is characteristic in LCs showing the V-shaped switching, and is not observable in typical ferroelectric and antiferroelectric LCs. The dynamic response of SHG was successfully simulated using the two-dimensional Langevin type potential model.