Laser based in-situ and standoff detection of chemical warfare agents and explosives

C. Kumar N. Patel

doi:10.1117/12.835883

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17 September 2009 Laser based in-situ and standoff detection of chemical warfare agents and explosives

C. Kumar N. Patel

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Proceedings Volume 7484, Optically Based Biological and Chemical Detection for Defence V; 748402 (2009) https://doi.org/10.1117/12.835883
Event: SPIE Security + Defence, 2009, Berlin, Germany

Abstract

Laser based detection of gaseous, liquid and solid residues and trace amounts has been developed ever since lasers were invented. However, the lack of availability of reasonably high power tunable lasers in the spectral regions where the relevant targets can be interrogated as well as appropriate techniques for high sensitivity, high selectivity detection has hampered the practical exploitation of techniques for the detection of targets important for homeland security and defense applications. Furthermore, emphasis has been on selectivity without particular attention being paid to the impact of interfering species on the quality of detection. Having high sensitivity is necessary but not a sufficient condition. High sensitivity assures a high probability of detection of the target species. However, it is only recently that the sensor community has come to recognize that any measure of probability of detection must be associated with a probability of false alarm, if it is to have any value as a measure of performance. This is especially true when one attempts to compare performance characteristics of different sensors based on different physical principles. In this paper, I will provide a methodology for characterizing the performance of sensors utilizing optical absorption measurement techniques. However, the underlying principles are equally application to all other sensors. While most of the current progress in high sensitivity, high selectivity detection of CWAs, TICs and explosives involve identifying and quantifying the target species in-situ, there is an urgent need for standoff detection of explosives from safe distances. I will describe our results on CO2 and quantum cascade laser (QCL) based photoacoustic sensors for the detection of CWAs, TICs and explosives as well the very new results on stand-off detection of explosives at distances up to 150 meters. The latter results are critically important for assuring safety of military personnel in battlefield environment, especially from improvised explosive devices (IEDs), and of civilian personnel from terrorist attacks in metropolitan areas.

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C. Kumar N. Patel "Laser based in-situ and standoff detection of chemical warfare agents and explosives", Proc. SPIE 7484, Optically Based Biological and Chemical Detection for Defence V, 748402 (17 September 2009); https://doi.org/10.1117/12.835883

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