Far-infrared in vivo signature of human skin by terahertz time-domain spectroscopy using waveform rebuilding technology

We present terahertz time-domain spectroscopy characterization of human thumb skin in reflection measurement mode with waveform rebuilding technology. The thumb skin contacts one side of a high resistive silicon wafer with 3 mm thick, and here is an orthogonal incidence of the THz pulse putting on the other side of the wafer. We rebuild the time domain signal from silicon-skin interface as a sample signal by the signal from the air-silicon interface as a reference and a Fresnel transform function between them. Material parameters were calculated by minimizing the difference between the measured sample waveform and a rebuilt one in time domain. The double Debye model parameters for the thumb skin were fitted. The method has potential to research complex layer-structures in skin if a precise model is built.