title: Ultrabroadband terahertz spectroscopy of a liquid crystal.
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 time-domain 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.
authors.affiliation: Fachbereich Physik, Philipps-Universität Marburg, Hans-Meerwein-Straße MZG C06, 35032 Marburg, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Vieweg
authors.forename: B M
authors.initials: BM
authors.lastname: Fischer
authors.forename: M
authors.initials: M
authors.lastname: Reuter
authors.forename: P
authors.initials: P
authors.lastname: Kula
authors.forename: R
authors.initials: R
authors.lastname: Dabrowski
authors.forename: M A
authors.initials: MA
authors.lastname: Celik
authors.forename: G
authors.initials: G
authors.lastname: Frenking
authors.forename: M
authors.initials: M
authors.lastname: Koch
authors.forename: P U
authors.initials: PU
authors.lastname: Jepsen
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D050866:Liquid Crystals / Q000737:chemistry* / Q000528:radiation effects; D012031:Refractometry / Q000295:instrumentation*; D055068:Terahertz Spectroscopy / Q000295:instrumentation*