Continuous phase modulation in polymer-stabilized liquid crystals

摘要

Continuous optical phase modulation was systematically investigated in a nematic host liquid crystal (LC), which was stabilized with in-situ generated photopolymer. Various driving modes were investigated. With presence of a chiral dopant, polarization independent and fast electro-optic responses were found in both blue phase mode and uniformly standing helix mode. Anyway, high driving voltages ＞ 100 V were required to achieve phase modulation depths ＞ π in reflective test cells with planar electrodes. In contrast, much lower driving voltages ＜ 15 V were required in a polymer-network LC based on the same host LC if no chiral dopant was present. In this driving mode, high phase contrast and sums of response times (t_(on)+t_(off)) ≈ 3 - 4 ms were found, fast enough to achieve 200-400 Hz modulations.