THz spectroscopic imaging of concealed chemicals using is-TPG

In 2003, we reported the first-ever development of a spectral imaging system using a terahertz (THz) wave parametric oscillator (TPO). The system has a dynamic range below four orders of magnitude, which enables it to identify reagents only through thin envelopes using spectral imaging. Recently, we succeeded in developing a high power and high sensitivity THz wave spectral imaging system using injection-seeded THz parametric generation and detection, which has achieved a dynamic range of 100 dB. In this study, the new spectral imaging system successfully identified reagents through thicker material than the thin envelopes used previously.