Enhancement of Photosensitivity of Photorefractive Ferroelectric Liquid Crystal Blends to Green and Red Wavelength Regions Using Oligothiophene Photoconductive Dopants

The photorefractive effect can be used to generate rewritable holograms in a material, and it is utilized in various devices, including three-dimensional displays, optical tomography units, novelty filters, phase conjugate wave generators, and optical amplifiers. Ferroelectric liquid crystal (FLC) blends composed of a smectic liquid crystalline mixture, a chiral photoconductive dopant, and an electron trap reagent exhibit significant photorefractivity together with rapid responses. In previous studies, terthiophene derivatives were used as chiral photoconductive dopants and the resulting photorefractive effects were examined at 488 nm. In order to utilize the photorefractive ferroelectric liquid crystals in practical devices such as photoacoustic interferometers and ultrasound imaging units, the wavelength sensitivity of the material should be extended to longer regions. In the present work, chiral dopants possessing quarter-thiophene chromophores, sexithiophenes, and other photoconductive compounds with ...