6 August 1998 Explosive vapor detection via mid-infrared laser spectroscopy
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Accurate explosives detection would be an effective defense/deterrent against bomb attacks. Chemical vapor sensing has the potential to be both specific and sensitive. The work descried here involves the use of mid-IR laser spectroscopy to detect the presence of nitro-group based explosive vapors. Two different singly-resonant Silver Gallium Selenide OPOs were examined for use as the spectroscopy source: one was pumped with a 1.319 micrometers Nd:YAG laser, and the other was pumped by a 1.57 micrometers KTP/Nd:YAG OPO-laser. Both OPOs can be angle-tuned over wavebands of interest, producing coherent mid-IR idler output power at 5-8 micrometers , as well as near-IR outputs. Current results indicate that output energies of approximately 300 (mu) J in the mid-IR can be generated from 10 mJ of pump energy. The OPO outputs can be used to detect chemical vapors using a sample-reference absorbance experiment. Both OPO outputs are passed through a cell containing the vapor to be measured. The mid-IR output is attenuated by the strong absorption of the vapors, while the near-IR output, being unabsorbed, serves as a reference. The ratio measurement has a shot-noise limited accuracy better than one part per million absorbance.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Frank J. Effenberger, Frank J. Effenberger, Alvaro G. Mercado, Alvaro G. Mercado, } "Explosive vapor detection via mid-infrared laser spectroscopy", Proc. SPIE 3383, Electro-Optical Technology for Remote Chemical Detection and Identification III, (6 August 1998); doi: 10.1117/12.317640; https://doi.org/10.1117/12.317640

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