Spectral investigation of nematic liquid crystals with high optical anisotropy at THz frequency range

Abstract

Abstract Liquid crystals (LCs) with high optical anisotropy are very desirable for different applications in devices, such as filters, phase shifters, or phase gratings [T. Göbel, P. Meissner, A. Gaebler, M. Koeberle, S. Mueller, and R. Jakoby, Dual-Frequency Switching Liquid Crystal Based Tunable THz Filter, CLEO, Baltimore, MD, 2009; C.-Y. Chen, T.-R. Tsai, C.-L. Pan, and R.-P. Pan, Room temperature terahertz phase shifter based on magnetically controlled birefringence in liquid crystals, Appl. Phys. Lett. 83 (2003), pp. 4497–4499; and C.-J. Lin, C.-H. Lin, Y.-T. Li, R.-P. Pan, and C.-L. Pan, Electrically controlled liquid crystal phase grating for terahertz waves, IEEE Photon. Technol. Lett. 21 (2009), pp. 730–732]. We present spectral studies of LCs with large optical anisotropy in the range from 0.3 to 3 THz. Nematic LC mixtures which have Δn > 0.30 for visible frequency range, i.e., 1825 (Δn = 0.42 at 633 nm) were measured. Properties of LC materials like birefringence, absorption coefficients, and refractive indices for ordinary and extraordinary polarization in THz range were obtained. Orientation of LC was done by a high electric field. Measurements were performed using a TDS spectra 3000 spectrometer. Keywords: liquid crystalbirefringencespectroscopyView correction statement:Corrigendum Acknowledgements This article was financially supported by the Polish Ministry of Sciences and Higher Education, No. O R00 0144 12 "Tunable liquid crystal transducers for THz and GHz frequency range" and the Key Project POIG.01.03.01-14-016/08 "New Photonic Materials and their Advanced Applications".