Spectroscopic Imaging Using Terahertz Waves

Abstract

Non-destructive inspection equipment using terahertz waves is expected to be used in various sectors such as safety and security. The injection-seeded terahertz parametric generator (is-TPG) is suitable for the non-destructive detection of illicit drugs and explosives concealed in mail because of its high power generation and sensitive detectors. This study examined a terahertz spectrometry method suitable for the non-destructive detection of chemicals concealed in mail envelopes. We compared the transmission spectra of three saccharides in different covering materials using is-TPG and terahertz time-domain spectroscopy. In addition, we carried out terahertz spectroscopic imaging on chemicals concealed in thick mail envelopes. As a result, we demonstrated that spectrometry or spectroscopic imaging using is-TPG is effective in detecting chemicals concealed in such items.