Security screening system based on terahertz-wave spectroscopic gas detection

Minable terahertz (THz)-wave absorption spectroscopy is a promising technique to detect trace gases suspended in ambient air owing to their strong absorption fingerprints in the THz-wave spectral region. Here, we present a THz-wave spectroscopic gas detection platform based on a frequency-tunable injection-seeded THz-wave parametric generator and compact multipass gas absorption cells. Using a 1.8-m-path-length multipass cell, we detected gas-phase methanol (CH3OH) down to a trace concentration of 0.2 ppm at the 1.48 THz transparent atmospheric window. We also developed a transportable walk-through screening prototype using a 6-m-path-length multipass cell to identify suspicious subjects. Our results demonstrate the potential of the proposed system for security screening applications. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

This study introduces a gas detection platform based on THz-wave spectroscopy, which can detect and identify trace gases. By using multipass gas absorption cells of different path lengths, gas components can be sensitively detected and applied to security screening applications.