[Terahertz Spectroscopic Investigation of Substrate Materials for Biological Application in the Frequency Range of 1～15 THz]

Abstract

As emerging modalities, terahertz time-domain spectroscopy and imaging have been widely applied to investigate the optical properties of different biological tissues. The substrate materials are usually needed for biological spectroscopic measurements. The ultra-broadband and facility in remote sensing of the terahertz air-biased-coherent-detection (ABCD) system mean it is a good potential tool for the spectroscopic study of biological tissues. In this paper, the optical parameters of four typical substrate materials (quartz, high-density polyethylene, teflon and paraffin) are measured using terahertz ABCD spectrometer. The absorption coefficients and refractive indices are presented in the frequency range of 1～15 THz. It is demonstrated that high-density polyethylene and paraffin are good candidates as sample substrate for broadband terahertz biological spectroscopic measurement. However, quartz and teflon which are common substrate materials in narrowband (0.1～3 THz) terahertz system can not be utilized in high terahertz frequency range because they have strong absorption above 5 THz.