標題: Recent progress in liquid crystal THz optics - art. no. 61350D
作者: Pan, Ci-Ling
Pan, Ru-Pin
光電工程學系
Department of Photonics
關鍵字: THz;liquid-crystal devices;far Infrared;phase shifters;wave plate;Lyot filter
公開日期: 2006
摘要: 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 birefrincrence 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-field-controlled birefringence in nematic 5CB gives a phase shift as large as 108 degrees at 1.0 THz. Phase shift exceeding 360 degrees at 1 THz, an important milestone, was realized by using a sandwiched LC (E7, Merck) cell as thick as 3 nun. 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 similar to 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.
URI: http://hdl.handle.net/11536/17130
http://dx.doi.org/10.1117/12.644527
ISBN: 0-8194-6177-6
ISSN: 0277-786X
DOI: 10.1117/12.644527
期刊: Liquid Crystal Materials, Devices, and Applications XI
Volume: 6135
起始頁: D1350
結束頁: D1350
Appears in Collections:Conferences Paper


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