Orientation analysis of liquid crystal (LC) devices is important for understanding and controlling light propagation behavior in these devices. Blue phases (BPs)─unique LC phases that self-organize into three-dimensional helical structures─are candidate materials for LC-based reflective diffractors. We realized BPII deflectors with large diffraction angles using one-dimensional surface alignment patterns. We analyzed the BPII lattice arrangement in the deflector based on Bragg reflections and demonstrated that the lattice structure was slanted with respect to the substrate, which was confirmed using transmission electron microscopy. In addition, we calculated the similarity between the alignment pattern on the substrate surface and the director arrangement of BPII near the interface, confirming that the structure observed experimentally matched the most probable calculated structure. Thus, this study contributes to the optical design of BPII deflectors and provides information on the orientation mechanism in high-order self-organizing soft matter structures.
Keywords: blue phase II; diffractor; liquid crystal; pattern alignment; photonic crystal; transmission electron microscopy.