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Polarization-Independent Liquid Crystal Devices, Yi-Hsin Lin
Polarization-Independent Liquid Crystal Devices, Yi-Hsin Lin
Electronic Theses and Dissertations
Liquid crystal (LC) devices can be operated as amplitude modulators and phase modulators. LC amplitude modulation is commonly used in liquid crystal display (LCD) while phase-only modulation is useful for laser beam steering, tunable grating, prism, lens, and other photonic devices. Most LC devices are polarization dependent and require at least one polarizer. As a result, the optical efficiency is low. To enhance display brightness, a power hungry backlight has to be used leading to a high power consumption and short battery life. In a LC phase modulator, the polarization dependent property complicates the laser beam steering system. It is …
Propagation Effect In Inhomogeneous Media, Including Media With Light-Induced And Fixed Gratings, Chang-Ching Tsai
Propagation Effect In Inhomogeneous Media, Including Media With Light-Induced And Fixed Gratings, Chang-Ching Tsai
Electronic Theses and Dissertations
Optical waves propagation in various types of volume gratings, materials with constant impendence and optical fibers are studied. Instability of crossphase modulation and of Energy transfer via GRON-type (Grating-type Orientational Nonlinearity in Liquid Crystal) Stimulated Scattering is numerically observed. Two diffractive optical elements made of volume gratings are suggested and analyzed. A transmission hologram based on the analogy with Stimulated Raman Adiabatic Passage (STIRAP) in nonlinear optics is proposed. This transmission hologram demonstrates high diffraction efficiency and low sensitivity to polarization and hologram strength. The other is a reflection hologram with two crossed-gratings. It features good angular selectivity in comparison …