Luận văn Liquid Crystal Devices with In-Plane Director Rotation (Chris Desimpel)

Liquid crystals are a widely used material in all kinds of optical applica-tions. The growing importance of liquid crystals as a versatile material in optical setups rises from their unique features. Optically, nematic liquid crystals are uniaxially birefringent and thus modify the polar-ization state of the light wave propagating through the material. The electrical anisotropy allows to reorient the uniaxial axis, also known as the director, by application of an externally applied electric field. Therefore, liquid crystals serve as an electrically controllable birefrin-gent layer. The most familiar application of liquid crystals exploiting the opti-cal and electrical anisotropy, is the liquid crystal display (LCD). Liquid crystal displays acquired an important position on the display market because they are lightweight, easy to produce and use a limited amount of power. The research on liquid crystals is still very active, but the focus is moving gradually away from pure display research. The unique fea-tures of liquid crystals are now exploited in totally different domains. Some of the new applications like Spatial Light Modulators are closely related to displays, while others such as phase gratings, wave plates and solitary waves are of a totally different nature. A common aspect of many new research topics is miniaturization. Also in new liquid crystal devices, the involved electrodes and surface topologies have mi-crometer scale features. This leads to microscopic variations inside the liquid crystal material. Microscopic changes in an optical material in-duce special effects such as diffraction and scattering of the transmitted light which require further study.