Fabrication and studies of three-dimensional photonic crystals based on polymer-dispersed liquid crystal films
| Autor: | Yi-Fang Chou, 周依芳 |
|---|---|
| Rok vydání: | 2009 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 97 This thesis studies three-dimensional (3D) photonic crystal (PC) and quasi photonic crystal (QPC) based on polymer dispersed liquid crystal (PDLC) films using two-beam interference with multi-exposures. Such a method simplifies the experimental setup in comparison with conventional holographic approach, and allows us to fabricate a large area (1x1 cm2) PC. Experimentally, one beam is incident normally onto the PDLC film, and the other beam is incident at an angle of 38.9°. Two beams are overlapped at the sample. Three and five exposures are made to fabricate the PDLC PCs, and between each exposure, the sample is rotated 120° and 72°, respectively along the normal of the sample surface. The photonic crystals obtained possess face-cubic center, and ten-fold rotation symmetry structures for the samples with three and five exposures, respectively. The structures of the fabricated PCs probed using scanning electron microscope (SEM) are found to agree with theory qualitatively. Deviation of the lattice spacing is 3~15 %. Furthermore, diffraction and dispersion effects of these PCs are systematically studied. The diffraction patterns agree well with theory based on Fourier transformation approach. It is also demonstrated that the diffraction efficiency of the 3D PCs can be electrically controllable. And the PCs possess the superprism effect. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|