Publication date: 2012
Document VersionPublisher's PDF, also known as Version of record Link back to DTU Orbit Citation (APA): Vieweg, N., Fischer, B. M., Reuter, M., Kula, P., Dabrowski, R., Celik, M. A., ... Jepsen, P. U. (2012). Ultrabroadband terahertz spectroscopy of a liquid crystal. Optics Express, 20(27) Abstract: Liquid crystals (LCs) are becoming increasingly important for applications in the terahertz frequency range. A detailed understanding of the spectroscopic parameters of these materials over a broad frequency range is crucial in order to design customized LC mixtures for improved performance. We present the frequency dependent index of refraction and the absorption coefficients of the nematic liquid crystal 5CB over a frequency range from 0.3 THz to 15 THz using a dispersion-free THz timedomain spectrometer system based on two-color plasma generation and air biased coherent detection (ABCD). We show that the spectra are dominated by multiple strong spectral features mainly at frequencies above 4 THz, originating from intramolecular vibrational modes of the weakly LC molecules. A 38(6), 3098-3100 (1988). 36. J. P. Perdew, "Density-functional approximation for the correlation energy of the inhomogeneous electron gas," Phys. Rev. B 33, 8822-8824, Erratum: B 34, 7406 (1986). 37. A. Schäfer, H. Horn, and R. Ahlrichs, "Fully optimized contracted Gaussian basis sets for atoms Li to Kr," J.