Precisely THz spectroscopy measurement of a three-layer structure using THz-TDS waveform rebuilding technology

We extracted optical material parameter of a middle sample layer in a three-layer structure from THz time-domain transmission spectroscopy by waveform rebuilding technology. The sample waveform is rebuilt by a reference signal in air and the transfer function of three-layer structure with liquid as a sample. Material parameters were calculated by minimizing the difference between the measured sample waveform and a rebuilt one in time domain. The method has wide application in the investigation of liquids in a known-thickness cuvette with high absorption in THz range.