Photorefractive effect in ferroelectric liquid crystals containing oligo-thiophene chiral compounds

The photorefractive effect in photoconductive ferroelectric liquid crystals (FLCs) that contain oligo-thiophene chiral compounds was investigated. Ter-thiophene and quarto-thiophene compounds with chiral structures were chosen as the photoconductive chiral compounds and mixed with an achiral smectic C liquid crystal. The mixtures exhibit the ferroelectric chiral smectic C phase. The photorefractivity of the mixtures was investigated by two-beam coupling experiments. It was found that the FLCs containing the photoconductive chiral compound exhibit a large gain coefficient of over 990 cm -1 and a fast response time of 1.7 ms.