Light-Driven Liquid Crystal Circular Dammann Grating Fabricated by a Micro-Patterned Liquid Crystal Polymer Phase Mask

Photoaligning and Photopatterning: New LC Technology

We demonstrate a physical model of photoalignment and photopatterning based on rotational diffusion in solid azo-dye nanolayers. We also highlight the new applications of photoalignment and photopatterning in display and photonics such as: (i) liquid crystal (LC) E-paper devices, including optically rewritable LC E-paper on flexible substrates as 3D E-paper, as well as optically rewritable technology for photonics devices; (ii) photonics LC devices, such as LC Switches, polarization controllers and polarization rotators, variable optical attenuators, LC filled photonic crystal fiber, switchable diffraction grating; (iii) patterned micro-polarizer array using photo-alignment technology for image sensor; (iv) electrically tunable liquid crystal q-plates; (v) electrically switchable liquid crystal Fresnel lens; (vi) liquid crystal optical elements with integrated Pancharatnam-Berry phases. We are sure, that in the field of (LC), the main point is no longer display research, but new photonic applications of LC are emerging in telecommunication, fiber optical communication systems, sensors, switchable lenses, LC light converters and other LC photonics devices.

Dual-mode liquid crystal grating based on photo- and nanoparticle-induced alignment effects

A silica-nanoparticle-and-azo-dye-doped liquid crystal (LC) phase grating with multistable and dynamic modes based on photo- and nanoparticle-induced alignments was demonstrated. The photoalignment suppressed the electrophoretic movement of the silica nanoparticles in the hybrid aligned nematic (HAN) LC cell to maintain the vertical orientation of LCs during the electrical operation process by means of the azo dyes adsorbed on the silica networks in the homogeneously aligned side of the sample, and contributed two LC structures to form a grating. Through the excitation of a DC pulse with proper polarity and an AC voltage, the multistable and dynamic diffraction efficiencies of the grating were achieved, respectively, by electrophoretically controlled silica nanoparticles and the electrically controlled birefringence effect of LCs.

Fast Switchable Dual-Model Grating by Using Polymer-Stabilized Sphere Phase Liquid Crystal

We demonstrated a fast switchable dual-model grating based on a polymer-stabilized sphere phase liquid crystal. To form binary periodicity layers, the polymer-stabilized sphere phase liquid crystal precursor was sequence ultraviolet cured at an isotropic and sphere phase. This grating jointly modulated both the phase and the amplitude, had six times the diffraction efficiency of that fabricated with polymer-stabilized blue phase liquid crystal. Moreover, the dual-model tunable grating shown polarization-independent and submillisecond response time, which may hold a great potential application in diffractive optics.