FAR-INFRARED, FREQUENCY DEPENDENT, COMPLEX DIELECTRIC CONSTANTS OF SEVERAL POLAR LIQUIDS

Abstract

The frequency dependent complex dielectric constant, $\hat{\varepsilon}(\omega) = \varepsilon_{1}(\omega) + i\varepsilon_{2}(\omega)$, spanning the range from 0 to 2 THz $(0 to 66.6 cm^{-1})$ has been measured for several polar liquids using time-domain Fourier transform THz beam spectroscopy. Liquids studeid include propanol, ethanol, methanol and water. The THz pulses are generated in the standard $fashion^{1}$ by illuminating the gap of a biased transmission line deposited on a GaAs substrate with visible pulses (780 nm) of 100 fs duration. The THz pulses are detected by an optically gated receiver that consists of a $30\mu m$ long antenna with a $5\mu m$ gap deposited on silicon-on-sapphire substrate. The temperature dependence of these spectra will be discussed.