title: Anisotropic terahertz dielectric responses of sodium nitrate crystals.
abstract: Terahertz (THz) spectroscopy has become an effective tool to characterize the low-frequency rotational and vibrational modes of molecules. In addition, novel THz dielectric responses and optical properties on the basis of molecular rotation and vibration have attracted lots of attention because of their potential application in THz devices. In this paper, the dielectric response of low-symmetric sodium nitrate crystals in the frequency range of 0.2-1.5 THz was experimentally demonstrated. Four absorption bands at 0.23, 0.47, 0.92, and 1.15 THz were observed in the dielectric spectra and were tentatively ascribed to the rotational motion of nitrate ions. Based on the molecular rotation mechanism, the dielectric anisotropy and dielectric resonance of the crystal were discussed in detail.
authors.affiliation: State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China. zhouji@mail.tsinghua.edu.cn.
authors.forename: Xiaojian
authors.initials: X
authors.lastname: Fu
authors.forename: Youting
authors.initials: Y
authors.lastname: Song
authors.forename: Changqing
authors.initials: C
authors.lastname: Sun
authors.forename: Ji
authors.initials: J
authors.lastname: Zhou