Novel liquid crystal devices for display and photonics based on non-uniform alignment

Liquid Crystal (LC) is widely used in the Display industry. Currently most of televisions, phones, computers and other electronic devices implement Liquid Crystal Displays (LCDs). The display system normally is composed of the backlight, the polarizer and the liquid crystal cell. The initial alignment of liquid crystal molecules is achieved by rubbing. The alignment of the LC molecules can only be changed by electric fields because these molecules have dipole moments along their directors, but not by any light. The backlight also consumes large amount of power. Optically Rewritable Liquid Crystal Display (ORW) makes use of the Photoalignment technique to achieve the image displays by exposing the LC cell with the polarized UV light. First the thermal stability of the photoalignment technique will be investigated to verify the quality of the photoalignment technique. 3D effect can also be integrated into the ORW cell with two methods: Stereoscopic and Auto-Stereoscopic. This thesis will discuss the procedure for preparing 3D ORW cells and show the experimental results. ORW cells can also find applications like phase grating devices. The grating patterns can be transferred from an amplitude mask to the cell. Liquid Crystals can also be used to make photonics devices because of its electro-optical properties. Most frequently seen are LC optical switches, phase retarders, sensors and lens. They usually derive from the birefringence of the refractive indices along the director and perpendicular to the director of a LC molecule. In this thesis, the beam steering devices which steers the beam continuously by changing the effective refractive index of the LC cell will be investigated. The principles, simulation and experimental results will be shown. To increase the efficiency, the simulation of the phase corrector will be discussed