A compact THz-TDS system for stable and quick measurements

A compact system of THz time-domain spectroscopy (THz-TDS), equipped to a mode-locked Er-doped fiber laser, has been developed. It enables quick measurements with a delay stage at the speed higher than 1 mm/s with the position accuracy of 001 mum. The typical duration of the single measurement is shorter than 30 s. The frequency-domain spectral range is between 0.04 and 4 THz and the dynamic range is wider than 10 5 . Its sample stage is adaptable for tablets, aqueous solutions, etc. For aqueous solutions, small-gap quartz cells have been designed and absorption spectra of the sample solution can be obtained in THz region similar to UV-Vis in spite of the strong absorbance of water.