Title page for etd-0616113-161122


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URN etd-0616113-161122
Author Ru-hsien Chiang
Author's Email Address No Public.
Statistics This thesis had been viewed 5350 times. Download 1 times.
Department Physics
Year 2014
Semester 1
Degree Ph.D.
Type of Document
Language zh-TW.Big5 Chinese
Title Studies and Fabrications of Cholesteric Liquid Crystal Gratings
Date of Defense 2014-09-24
Page Count 57
Keyword
  • grating
  • thermal effect
  • diffraction efficiency
  • cholesteric
  • stripe
  • Abstract This thesis demonstrates two tunable gratings based on cholesteric liquid crystals (CLCs). The first one is the thermally rotatable grating with hybrid-aligned (HBA) structures. Experiments reveal that the HBA-cholesteric texture has a uniformly striped domain, which forms a grating, when the ratio of the cell gap to the helical pitch (d/p) is in the range of 2~ 3. The stripe direction of the HBA-cholesteric grating rotates continuously under thermal and electrical effects. Furthermore, the HBA-cholesteric grating has a larger rotational angle under the thermal effect (~101゜) than under the electrical effect (~48゜). The second grating is an electrically switchable diffraction grating (ESDG) fabricated by filling the CLCs into the cell with slit electrodes. On one hand, with low voltage, the ESDG has high second order diffraction efficiency because of the alternating planar and fingerprint textures. With high voltage, on the other hand, the ESDG has high first order diffraction efficiency because of the alternating planar and homeotropic textures. The first and second order diffraction efficiencies of ESDG are electrically swapped. The maximum diffraction efficiency of the ESDG is approximately 32% at each grating mode.
    Advisory Committee
  • Chi-Yen Huang - chair
  • Chia-Rong Lee - co-chair
  • Tsung-Hsien Lin - co-chair
  • Ming-Shan Tsai - co-chair
  • Chie-Tong Kuo - advisor
  • Files
  • etd-0616113-161122.pdf
  • Indicate in-campus at 5 year and off-campus access at 5 year.
    Date of Submission 2014-09-25

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