THz time-domain spectroscopy of Nematic liquid crystal based on mode-locked Yb-doped fiber laser

We demonstrate a THz time-domain spectroscopy (TDS) system based on a mode-locked Yb-doped fiber laser as a pump source. A THz emission bandwidth of over 2.2 THz or more is achieved for 220 mm in free spacing and the signal-to-noise ratio is achieved more than 30 dB. As an application, THz spectroscopy of a nematic liquid crystal is measured and analyzed. The THz absorption spectrum of the cell was measured by applying an electric field to the E7 NLC cell. As a result, it was experimentally confirmed that as the electric field applied to the NLC cell increases, the absorption of the specific THz frequency of the cell decreases.