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A Multimodal Wide-Field Fourier-Transform Raman Microscope
Published on: December 30, 2025
Stand-off detection of explosives particles by multispectral imaging Raman spectroscopy
Henric Östmark1, Markus Nordberg, Torgny E Carlsson
1Department of Energetic Materials, Swedish Defence Research Agency (FOI), Grindsjön Research Centre, Tumba, Sweden. henric.oestmark@foi.se
Applied Optics
|October 22, 2011
Summary
This study presents a Raman multispectral imaging technique for detecting single explosive particles from a distance. The system successfully identified sulfur particles at 10 meters, demonstrating its potential for security applications.
Area of Science:
- Spectroscopy
- Analytical Chemistry
- Optical Engineering
Background:
- Stand-off detection of hazardous materials is crucial for security.
- Raman spectroscopy offers chemical specificity for material identification.
- Existing methods may struggle with single particle detection or environmental interference.
Purpose of the Study:
- To develop and demonstrate a Raman multispectral imaging technique for stand-off detection of single explosive particles.
- To evaluate the system's performance in identifying various explosive compounds.
- To assess the system's robustness against environmental variations.
Main Methods:
- Utilized a frequency-doubled Nd:YAG laser for illumination.
- Employed a Schmidt-Cassegrain telescope and a liquid-crystal tunable filter for signal collection and wavelength selection.
- Used a gated intensified charge-coupled device (ICCD) detector to record multispectral images.
- Analyzed pixel-by-pixel Raman spectra using correlation and least-square fitting for identification.
Main Results:
- Acquired multispectral Raman images of sulfur, ammonium nitrate, 2,4-dinitrotoluene, and 2,4,6-trinitrotoluene at a 10 m stand-off distance.
- Successfully detected single sulfur particles at 10 m.
- The system demonstrated relative insensitivity to environmental and light variations.
Conclusions:
- The developed Raman multispectral imaging technique is effective for stand-off detection of single explosive particles.
- The system shows promise for real-world security applications requiring sensitive and specific material identification.
- Further development could enhance detection limits and expand the library of identifiable compounds.
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