Infrared spectroscopy is a powerful laboratory technique for detection of and discrimination between hazardous chemicalthreats, such as explosive materials, and non-hazardous background chemicals. Transitioning this method to the fieldhowever has significant challenges, especially when being deployed as a standoff, or proximate standoff technique. Themain issue for proximate standoff detection lies in the ability of a system to collect enough reflected light from a sourceilluminating a surface to provide chemical information for the target material. This issue is further exacerbated when tryingto detect highly scattering materials on surfaces, such as particulates or powders, which are typical forms for explosivematerials. While diffuse reflectance from such materials provides good chemical vibrational absorption band information,when being collected at some distance away from the sample, this scattering provides a significant detection challenge.We present detection results for highly scattering inkjet printed explosive standards, collected at proximate standoffdistances (~ 0.5 m) in a laboratory environment. Discrimination between these standards using both conventional infraredspectroscopy, as well as NRL’s unique optical filter based biomimetic sensing approach are discussed. This work is meantto inform the rational development of portable infrared optical sensors for detection of explosives at proximate distancesin operational environments.
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