Browsing by Author "Shih, Chih-Chang"

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Magnetically tunable metallic photonic crystals immersed in liquid crystal for terahertz wave
(2012)
Pan, Ru-Pin
;
Shih, Chih-Chang
;
Tang, Tsung-Ta
;
Wang, Yow-Gwo
;
Wu, Hsin-Ying
We investigated the phenomena of a metallic photonic crystal (MPC) immersed in liquid crystal. According to our design, the photonic crystal has specific photonic band gap (PBG) and can be utilized as a filter. The device is filled with nematic liquid crystal (NLC), MDA-00-3461. The refractive indices of NLC can be magnetically controlled by reorienting the NLC molecules. Consequently, the corresponding PBG and the filtering performance of the device are tunable. According to our experimental results, the low frequency boundary of PBG at 0.121 THz can be blue shifted by 6.17 GHz, and the high frequency boundary of PBG at 0.175 THz can be shifted to the blue by 11.04 GHz. As a tunable THz filter, the peak transmittance at 0.187 THz can be blue shifted by 3.66 GHz.
THz Optical Constants of the Liquid Crystal MDA-00-3461
(2011)
Ku, Cheng-Pin
;
Shih, Chih-Chang
;
Lin, Chia-Jen
;
Pan, Ru-Pin
;
Pan, Ci-Ling
We have measured the far infrared optical constants of MDA-00-3461 at 25 degrees C by using terahertz time-domain spectroscopy. The extraordinary and ordinary refractive indices of MDA-00-3461 are n(e) approximate to 1.74 and n(o) approximate to 1.54, or a birefringence of 0.20 from 0.3 to 1.4 THz. The extinction coefficient of MDA-00-3461 is relatively small. There are no absorption peaks in the frequency range investigated.