This paper describes the design of a deep-UV Raman imaging spectrometer operating with an excitation wavelength
of 228 nm. The designed system will provide the ability to detect explosives (both traditional military explosives
and home-made explosives) from standoff distances of 1-10 meters with an interrogation area of 1 mm x 1 mm to
200 mm x 200 mm. This excitation wavelength provides resonant enhancement of many common explosives, no
background fluorescence, and an enhanced cross-section due to the inverse wavelength scaling of Raman scattering.
A coded-aperture spectrograph combined with compressive imaging algorithms will allow for wide-area
interrogation with fast acquisition rates. Coded-aperture spectral imaging exploits the compressibility of
hyperspectral data-cubes to greatly reduce the amount of acquired data needed to interrogate an area. The resultant
systems are able to cover wider areas much faster than traditional push-broom and tunable filter systems. The full
system design will be presented along with initial data from the instrument. Estimates for area scanning rates and
chemical sensitivity will be presented. The system components include a solid-state deep-UV laser operating at 228
nm, a spectrograph consisting of well-corrected refractive imaging optics and a reflective grating, an intensified
solar-blind CCD camera, and a high-efficiency collection optic.
We design and develop a low-cost pyroelectric detector-based IR motion-tracking system. We study the characteristics of the detector and the Fresnel lenses that are used to modulate the visibility of the detectors. We build sensor clusters in different configurations and demonstrate their use for human motion tracking.
We have developed a class of aperture coding schemes for Remote Raman
Spectrometers (RRS) that remove the traditional trade-off between
throughput and spectral resolution. As a result, the size of the
remote interrogation region can be driven by operational, rather than
optical considerations. In this paper we present the design of our
coded-aperture standoff spectroscopy system as well as experimental data collected while making remote measurements.
Human bodies are very good heat sources with peak emission wavelength of about 9?m. We use pyroelectric detectors that are differential in nature to detect human motion by their heat emissions. Coded Fresnel lens arrays create boundaries in space which helps to localize the human motion as well as classification. We design and implement a low-cost biometric tracking system using off-the-shelf components. We demonstrate tracking and classification using sensor clusters of dualelement pyroelectric detectors with coded Fresnel lens arrays.
We have developed a class of aperture coding schemes for Remote
Raman Spectrometers (RRS) that remove the traditional trade-off
between throughput and spectral resolution. As a result, the size
of the remote interrogation region can be driven by operational,
rather than optical considerations. We present theoretical
arguments on the performance of these codes and present data from
where we have utilized these codes in other spectroscopy efforts.