Instrumentation of terahertz time-domain spectroscopic system including two kinds of THz-radiation source

We designed a THz time-domain spectroscopic system including two kinds of THz-radiation source, i.e., low-temperature-grown GaAs photoconductive switching substrate and 4- dimethylamino-N-methyl- 4-stibazolium tosylate (DAST) crystal. The detector is common, low-temperature-grown GaAs photoconductive switching substrate, for two sources which can be replaced one another. The frequency-domain spectral ranges are 0.04-4.0 THz and 0.1-8.0 THz for the wave sources of low-temperature-grown GaAs photoconductive switching substrate and DAST crystal, respectively. The spectral data for pellet samples indicate that two kinds of THz-radiation source provide complementary information and extend the application of THz-TDS.