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We demonstrate the use of an active hyperspectral sensor for detection and recognition of persons in snowy foliage. The sensor employs a tunable broadband supercontinuum light source for remote spectrum measurement. An algorithm based on support vector machines is used in real-time to classify the object, from which the supercontinuum laser pulse scattered. We present results for person detection during simulated illegal border cross activities in snowy terrain.

There is a need for sensor technologies capable of identifying illegal border crossings through foliage. In this work, we study the use of a novel active hyperspectral sensor for remote identification of persons and vehicles through foliage. The AHS sensor is based on a continuously tunable near-infrared supercontinuum light source and a microelectromechanical Fabry-Pérot interferometer for transmission band selection. Real-time spectral detection algorithms are used to identify the targets based on the spectral content of the back-scattered light. Preliminary results are presented from both in-lab and outdoors.

Complex human physiological processes create the stable isotopic composition of exhaled carbon dioxide (eCO

We demonstrate optical unlocking of a cavity resonance in a mid-infrared (MIR) quantum cascade laser (QCL) cavity ring-down spectrometer using a low-power multimode near-infrared (NIR) laser diode. A NIR laser with a center wavelength of 1310 nm is injected into a QCL whose amplitude and frequency are modulated as a result. The shift in frequency leads to a rapid interruption of the cavity resonance. The optical method is compared to cavity interruption with a current step by measuring ring-down times in a high-finesse optical cavity, coupled with a QCL with a center wavelength of 4.5 μm. The results indicate the comparable performance of the all-optical method with the more conventional current modulation, but with significantly reduced bandwidth requirements for the QCL driver, opening the way to other potential applications in MIR laser spectroscopy.

A tunable laser absorption spectrometer (TLAS) was developed for the simultaneous measurement of δ13C and δD values of methane (CH4). A mid-infrared interband cascade laser (ICL) emitting around 3.27 µm was used to measure the absorption of the three most abundant isotopologues in CH4 with a single, mode-hop free current sweep. The instrument was validated against methane samples of fossil and biogenic origin with known isotopic composition. Three blended mixtures with varied biogenic content were prepared volumetrically, and their δ13C and δD values were determined. Analysis demonstrated that, provided the isotopic composition of the source materials was known, the δ13C and δD values alone were sufficient to determine the biogenic content of the blended samples to within 1.5%.

We present a compact and real-time analyser for δ 13C-CO2 and δ 18O-CO2 isotope ratios of CO2 in exhaled breath. The instrument exhibits major improvements compared to instrumentation currently available for isotope-selective diagnostics.

A hyperspectral remote sensing instrument employing a novel near-infrared supercontinuum light source has been developed for active illumination and identification of targets. The supercontinuum is generated in a standard normal dispersion multi-mode fiber and has 16 W total optical output power covering 1000 nm to 2300 nm spectral range. A commercial 256-channel infrared spectrometer was used for broadband infrared detection. The feasibility of the presented hyperspectral measurement approach was investigated both indoors and in the field. Reflection spectra from several diffusive targets were successfully measured and a measurement range of 1.5 km was demonstrated.

The aim of this work was to develop a cost effective hyperspectral instrument and to demonstrate the acquisition of IR reflection spectra over long distances.