title: New terahertz dielectric spectroscopy for the study of aqueous solutions.
abstract: We present the development of a high precision, tunable far-infrared (terahertz) frequency-domain dielectric spectrometer for studying the dynamics of biomolecules in aqueous solutions in the gigahertz-to-terahertz frequency. As an important benchmark system, we report on the measurements of the absorption and refractive index for liquid water in the frequency range from 5 GHz to 1.12 THz (0.17-37.36 cm(-1) or 0.268-60 mm). The system provides a coherent radiation source with power up to 20 mW in the gigahertz-to-terahertz region. The dynamic range of our instrument reaches 10(12) and the system achieves a spectral resolution of less than 100 Hz. The temperature of samples can be controlled precisely with error bars of ±0.02 °C from 0 °C to 90 °C. Given these attributes, our spectrometer provides unique capabilities for the accurate measurement of even very strongly absorbing materials such as aqueous solutions.
authors.affiliation: Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA.
authors.forename: Deepu K
authors.initials: DK
authors.lastname: George
authors.affiliation: Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Charkhesht
authors.affiliation: Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA.
authors.forename: N Q
authors.initials: NQ
authors.lastname: Vinh
mesh_terms: D045424:Complex Mixtures / Q000032:analysis* / Q000737:chemistry*; D058266:Dielectric Spectroscopy / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012996:Solutions; D055068:Terahertz Spectroscopy / Q000295:instrumentation*; D014867:Water / Q000032:analysis* / Q000737:chemistry*
chemical_list: D045424:Complex Mixtures; D012996:Solutions; D014867:Water