Explosive detection using infrared laser spectroscopy

Abstract

Stand-off and extractive explosive detection methods for short distances are investigated using mid-infrared laser spectroscopy. A quantum cascade laser (QCL) system for TATP-detection by open path absorption spectroscopy in the gas phase was developed. In laboratory measurements a detection limit of 5 ppm*m was achieved. For explosives with lower vapor pressure an extractive hollow fiber based measurement system was investigated. By thermal desorption gaseous TATP or TNT is introduced into a heated fiber. The small sample volume and a fast gas exchange rate enable fast detection. TNT and TATP detection levels below 100 ng are feasible even in samples with a realistic contaminant background

Time resolved FTIR study of spectral tuning and thermal dynamics of mid-IR QCLs

“…Also, they become important infrared light sources with various applications in defense [1] and civilian fields [2]. QCLs deliver high power and are capable of lasing at room temperature.…”

Support vector machine classification of volatile organic compounds based on narrow‐band spectroscopic data

“…Many technologies have been recalled to contribute to this direction, such as X-rays-based technologies (capable for bulk detection of a wide range of substances but cannot be used to screen persons) [1][2][3], magnetic portals (for metal detection), millimeter or terahertz wave imagers (capable also for bulk detection only) [4][5][6][7], ion mobility spectrometry (currently one of the most efficient for explosives, drugs, and hidden persons trace detection) [8][9][10][11], and CO 2 sensors (capable for hidden person detection but with low reliability operation) [12,13]. Finally, midinfrared (MIR) spectroscopic methods have been widely used to trace the occurrence of chemical compounds for various applications, such as food analysis, air quality assessment, forbidden substance detection, and border security [14][15][16][17][18][19][20][21][22]. More specifically, MIR spectroscopy technology based on photoacoustic detection (MIRPAS) [23,24] appears as a new powerful tool to detect a very wide range of volatile organic compounds (VOCs) associated with the security agents of interest [25].…”

Multivariate Analysis in Vibrational Spectroscopy of Highly Energetic Materials and Chemical Warfare Agents Simulants

“…QCL-based setups are being developed for in the field applications such as breath analysis, environmental research, airborne measurements, security applications, laser-based isotope ratio measurements, and many others. In particular, for security applications, optical methods are advantageous because of their capability for remote and standoff detection [14,25,26]. Due to improvements in QCL development, mid infrared lasers operating at room temperature with high output powers in the CW regime are commercially available and make it possible to set up a ruggedized system that allows sensing of explosives and others materials outside the laboratory and the ability to enter real world scenarios.…”

“…Vibrational spectroscopy has demonstrated to be valuable for the detection of HEM, HME, CWA and Simulants (CWAS) and Toxic Industrial Compounds (TIC). In particular, infrared spectroscopy (IRS) and Raman spectroscopy (RS) in various modalities have played unique roles in threat compounds detection [6,[12][13][14][15][16][17][18][19]. IRS and RS can be employed for detection of Explosives and Chemical Warfare Agents, as well as other chemical and biological threats in airports, in military environments, in government buildings and other public safety places.…”