ABSTRACT Today’s Hazardous Materials (Haz/Mat) professionals and First Responders (fire and police) increasingly have to confront ever more hazardous and potentially deadly chemical spills and unknown chemical substances as a course of their daily activities. These activities typically require ascertaining the unknown substances’ identity followed by the institution of appropriate remediation activities and safety measures as commensurate with the toxicity of the substance. While most of these activities are of a routine nature, the increased daring of terrorists along with their increased access to chemical, biological and, in some cases, nuclear and radiological materials, has increased both the complexity and the hazards confronting these professionals. In light of the fact that the current generation of chemical sensors available to these First Responders require either sample acquisition (followed by sample preparation) or bringing the detector/sensor in close proximity to the unknown spill prior to knowing the identity of the substance in question, we decided to evaluate the efficacy of short-range Raman lidar (Light Detection and Ranging) towards the detection/identification of ground contamination. The following article provides a review of this “non-traditional” application of Raman lidar to the detection and identification of solid ground contamination and liquid chemical spills. A historical summary of the Raman lidar technique along with an introduction of Raman spectroscopy will be presented, and Raman spectra of CCl4 and C2Cl4 will be used as examples to illustrate pre-resonance and resonance effects. This is then followed by examples of two Raman lidar sensor platforms deployed for this “non-traditional” scenario along with the data acquisition techniques and experimental results.
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