Polymer‐Stabilized Blue Phase Liquid Crystals for Photonic Applications

Polymer‐stabilized blue phase liquid crystal (PS‐BPLC) is emerging as a promising candidate for next‐generation photonic applications due to its attractive features: nano‐scale structure that enables sub‐millisecond response time, self‐assembly that eliminates the need for surface alignment, and three‐dimensional cubic structure so that it is quasi‐isotropic without applied field. Here, we will look into the photonic properties of PS‐BPLC microscopically and macroscopically, and will focus on the non‐display photonic applications based on these properties. First we will give a general introduction to the polymer stabilization process, general photonic properties, electric field effects and desirable electro‐optical properties of PS‐BPLC. Next we will present applications based on the microscopic photonic properties in the cubic structures with double twist cylinders: photonic band gap, scattering and unwinding of the double twist structure under electric field. Then, we will cover applications based on the macroscopic refractive index change of PS‐BPLC under electric fields, whose mechanisms are further classified into phase retardation, phase modulation, and resonance condition change. Finally we will look into the remaining challenges and future perspectives of PS‐BPLC for photonic applications.