The optical constants of a nematic liquid crystal, 4′-<i>n</i>-pentyl-4-cyanobiphenyl (5CB), in the frequency range 0.3–1.4 THz were determined by terahertz (THz) time-domain spectroscopy. The real parts of the extraordinary refractive index <i>n</i><sub><i>e</i></sub> and the ordinary refractive index <i>n</i><sub><i>o</i></sub> of 5CB varied from 1.74 to 2.04 and from 1.59 to 1.83, respectively. Liquid-crystal 5CB exhibits a relatively small absorption loss in this frequency range. The birefringence of 5CB was found to be as large as 0.21. The experimental results indicate that liquid-crystal 5CB is potentially useful for device applications in the THz frequency range.
© 2003 Optical Society of America
(160.3710) Materials : Liquid crystals
(160.4760) Materials : Optical properties
(300.6270) Spectroscopy : Spectroscopy, far infrared
(300.6530) Spectroscopy : Spectroscopy, ultrafast
(320.7150) Ultrafast optics : Ultrafast spectroscopy
Tsong-Ru Tsai, Chao-Yuan Chen, Ci-Ling Pan, Ru-Pin Pan, and Xi-Cheng Zhang, "Terahertz Time-Domain Spectroscopy Studies of the Optical Constants of the Nematic Liquid Crystal 5CB," Appl. Opt. 42, 2372-2376 (2003)