Pinning effect on the photonic bandgaps of blue-phase liquid crystal

This study demonstrates the surface alignment induced pinning effects on blue phases. The morphologies of blue-phase platelets in a nonaligned cell become less uniform, and the photonic bandgap shifted over 120 nm during the cooling process. Comparing the different boundary conditions, the anchoring forces provide by homogeneous alignment can pin the blue-phase platelets, confine the photonic bandgap variation, and increase uniformity of the blue phase. This study also examines the pinning effect by the patternable photoalignment technique. Boundary anchoring forces have a significant effect on the morphology and photonic characteristics of the blue phase, making them applicable to practical applications. (C) 2011 Optical Society of America