Diffuse reflectance near infrared hyperspectral imaging is an important analytical tool for a wide variety of industries,
including agriculture, consumer products, chemical and pharmaceutical development and production. Using this
technique as a method for the standoff detection of explosive particles is presented and discussed. The detection of the
particles is based on the diffuse reflectance of light from the particle in the near infrared wavelength range where CH,
NH, OH vibrational overtones and combination bands are prominent.
The imaging system is a NIR focal plane array camera with a tunable OPO laser system as the illumination source. The
OPO is programmed to scan over a wide spectral range in the NIR and the camera is synchronized to record the light
reflected from the target for each wavelength. The spectral resolution of this system is significantly higher than that of
hyperspectral systems that incorporate filters or dispersive elements. The data acquisition is very fast and the entire
hyperspectral cube can be collected in seconds. A comparison of data collected with the OPO system to data obtained
with a broadband light source with LCTF filters is presented.
We present a novel hyperspectral imaging technique based on tunable laser technology. By replacing the broadband
source and tunable filters of a typical NIR imaging instrument, several advantages are realized, including: high spectral
resolution, highly variable field-of-views, fast scan-rates, high signal-to-noise ratio, and the ability to use optical fiber
for efficient and flexible sample illumination. With this technique, high-resolution, calibrated hyperspectral images over
the NIR range can be acquired in seconds. The performance of system features will be demonstrated on two example
applications: detecting melamine contamination in wheat gluten and separating bovine protein from wheat protein in
A compact tunable UV OPO laser system has been used for the real-time detection of aromatic hydrocarbon hazardous air pollution vapors at sub-ppb levels using the jet-REMPI (jet-cooled Resonance Enhanced Multi-Photon Ionization) technique. By combining spectral and molecular mass detection, this technique provides high chemical selectivity, allowing species identification even during direct sampling of complex real-world samples. The inherent sensitivity of the jet-REMPI also allows direct real-time detection of trace species without pre-concentration. However, applications of the technique have been confined to the laboratory, requiring a complex and delicate tunable UV laser source and mass spectrometer. The results of applying a less complex, compact low-resolution OPO laser system are presented, with the goal of furthering the development a complete compact jet-REMPI instrument.