Fig. 1. Schematic representation of the two-step exposure technique for the patterned alignment layer of the FLC CDG. (a) The exposure of polarized UV on the SD1 substrate; (b) the exposure of the SD1 substrate with the mask; (c) the FLC CDG cell with a single-side alignment; (d) the chemical formula of the SD1.

Fig. 2. (a) Microscopic photo of the FLC CDG under the crossed polarizer and analyzer. The horizontal yellow bar shows the scale ratio of 200 μm. Red arrows indicate the alignment directions. (b) Illustration of the molecule directions and the helical orientation with respect to the polarizer and analyzer in the odd and even zones. (c) and (e) are the textures of the FLC CDG under the electric field of two polarities; (d) and (f) represent the orientation of the FLC molecules for textures (c) and (e), respectively.

Fig. 3. For the eight-order FLC CDG, (a) the far-field diffraction patterns and (b) the corresponding light intensity profile.

Fig. 4. Switching time of the FLC CDG versus applied electric field. The magnitude of the driving frequency is set at 500 Hz. The inset figure shows the electro-optical response of the diffraction pattern.