In this thesis, we propose and demonstrate a simple and precise method for
measuring mm scaled cell gap by using terahertz time domain spectroscopy
(THz-TDS) system. This method allows us to measure the cell gap from 15mm to
1.5mm. In addition, the accuracy of measured thickness for the proposed method is
also discussed and analyzed. Meanwhile, a nematic liquid crystal BL006 with
birefringence as high as 0.27 in THz frequency range and its optical properties of
cholesteric liquid crystal (CLC) as mixing chiral materials are investigated and
reported. The ordinary refractive index and average effective refractive index at 20oC
are from 1.52 to 1.56 and from 1.61 to 1.64, respectively, in THz frequency ranging
from 0.2 THz to 1.4THz. In addition, we also demonstrate that cell filled with CLC is
with polarization independent property for THz radiation. Through the 5mm cell filled
CLC with diluted concentration of the dopant chiral material for decreasing the
critical voltage, an electric controlled polarization independent phase shifter with the
modulation depth exceeding 2pi is demonstrated. Furthermore, we also investigate the
driving field dependence of phase retardation and discuss the reliability.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0717112-173343 |
| Date | 17 July 2012 |
| Creators | Lin, Bo-Heng |
| Contributors | Tsung-Hsien Lin, Yi-Jen Chiu, Ann-Kuo Chu, Chao-Kuei Lee, Wei-Hung Su |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0717112-173343 |
| Rights | user_define, Copyright information available at source archive |
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