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Proceedings Paper

Recent progress in liquid crystal THz optics
Author(s): Ci-Ling Pan; Ru-Pin Pan
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Paper Abstract

Recently, there have been increasing interests in the study of liquid-crystal-based devices for application in the submillimeter wave or THz frequency range. In this paper, we present recent progress in liquid crystal THz optics from our group. Using time-domain THz spectroscopy, we have determined the complex indices of refraction of nematic liquid crystals, 5CB, PCH5 and E7 from 0.2 to beyond 1 THz. Significantly, the birefringence of 5CB and E7 are found to be as large as 0.2 at THz frequencies, while the absorption is negligible. Electrical-field and magnetic-field-controlled birefringence in LC were also investigated. A tunable room-temperature THz phase shifter using magnetic-fieldcontrolled birefringence in nematic 5CB gives a phase shift as large as 108° at 1.0 THz. Phase shift exceeding 360° at 1 THz, an important milestone, was realized by using a sandwiched LC (E7, Merck) cell as thick as 3 mm. The magnetically tuned LC phase shifter served as key components in a two-element tunable LC Lyot filter. The tuning range of the filter is from 0.388 to 0.564 THz or a fractional tuning range of ~ 40%. Our work clearly demonstrates the potential of liquid crystal devices for THz applications. Finally, we will present initial works on control of enhanced THz transmission through a metallic hole array with nematic liquid crystals. Our work clearly demonstrates the potential of liquid crystal devices for THz applications.

Paper Details

Date Published: 23 February 2006
PDF: 13 pages
Proc. SPIE 6135, Liquid Crystal Materials, Devices, and Applications XI, 61350D (23 February 2006); doi: 10.1117/12.644527
Show Author Affiliations
Ci-Ling Pan, National Chiao Tung Univ. (Taiwan)
Ru-Pin Pan, National Chiao Tung Univ. (Taiwan)


Published in SPIE Proceedings Vol. 6135:
Liquid Crystal Materials, Devices, and Applications XI
Liang-Chy Chien, Editor(s)

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