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Journal of the Optical Society of America B

Journal of the Optical Society of America B


  • Editor: Henry van Driel
  • Vol. 27, Iss. 9 — Sep. 1, 2010
  • pp: 1866–1873

The complex refractive indices of the liquid crystal mixture E7 in the terahertz frequency range

Chan-Shan Yang, Chia-Jen Lin, Ru-Pin Pan, Christopher T. Que, Kohji Yamamoto, Masahiko Tani, and Ci-Ling Pan  »View Author Affiliations

JOSA B, Vol. 27, Issue 9, pp. 1866-1873 (2010)

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We have used terahertz time-domain spectroscopy to investigate the complex optical constants and birefringence of a widely used liquid crystal mixture E7 in both nematic and isotropic phases ( 26 ° C 70 ° C ) . The extinction coefficient of E7 at room temperature is less than 0.035 and without sharp absorption features in the frequency range of 0.2–2.0 THz. The extraordinary ( n e ) and ordinary ( n o ) indices of refraction at 26 ° C are 1.690–1.704 and 1.557–1.581, respectively, giving rise to a birefringence of 0.130–0.148 in this frequency range. The temperature-dependent ( 26 ° C 70 ° C ) order parameter extracted from the birefringence data agrees with that in the visible region quite well. Further, the temperature gradients of the terahertz optical constants of E7 are also determined. The optical constants of E7 in the terahertz or sub-millimeter wave range are found to deviate significantly from values predicated by the usual extended Cauchy equations used in the visible and near-infrared.

© 2010 Optical Society of America

OCIS Codes
(000.6850) General : Thermodynamics
(120.4530) Instrumentation, measurement, and metrology : Optical constants
(140.7090) Lasers and laser optics : Ultrafast lasers
(160.1190) Materials : Anisotropic optical materials
(160.3710) Materials : Liquid crystals
(040.2235) Detectors : Far infrared or terahertz

ToC Category:
Ultrafast Optics

Original Manuscript: June 18, 2010
Revised Manuscript: July 1, 2010
Manuscript Accepted: July 5, 2010
Published: August 23, 2010

Chan-Shan Yang, Chia-Jen Lin, Ru-Pin Pan, Christopher T. Que, Kohji Yamamoto, Masahiko Tani, and Ci-Ling Pan, "The complex refractive indices of the liquid crystal mixture E7 in the terahertz frequency range," J. Opt. Soc. Am. B 27, 1866-1873 (2010)

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