Electrically tunable holographic polymer templated blue phase liquid crystal grating*
He Zheng-Honga),b), Chen Chao-Pinga)†, Zhu Ji-Lianga), Yuan Ya-Chaoa), Li Yana)‡, Hu Weia), Li Xiaoa), Li Hong-Jinga), Lu Jian-Ganga), Su Yi-Kaia)
       
Schematic diagrams of the fabrication procedure. (a) Stage 1: a mixture of monomers and liquid crystals fills the cell; (b) Stage 2: the HPDLC grating is formed under the alternating bright and dark interference fringes, then illuminated by an ultraviolet light to be stabilized; (c) Stage 3: the cell is immersed in acetone to wash out the liquid crystal and un-polymerized residuals. The remaining polymer template consists of the alternating polymer-rich and polymer-poor regions, which are denoted as regions I and II, respectively. A polymer-free gap is on the top of the polymer template, which is denoted as region III due to shrinking; and (d), Stage 4: the polymer template is refilled with a BPLC.