An open-path spectrometer for fast spatial detection and identification of gaseous plumes in a realistic environmental conditions is presented. Gases are released in a 500 m3 hall; detection and identification is performed by spectroscopic means—measuring the light spectral absorption (at 8 to 10 μm) by shining an external-cavity quantum cascade laser beam through the inspected volume. Real-time identification is demonstrated for gas plumes of CH2FCF3 (R134a) and CHF3 at a distance of 30 m round trip with a minimum identification level of 0.2 ppm (response times of 2 to 10 s). The relatively wide spectral coverage allows a high probability of detection (PD) and low probability for a false alarm to be obtained in these realistic conditions. It is also demonstrated that the use of several lines-of-sight improves PD as gas spreading in the hall in these conditions is slow and unpredictable.
In this paper we start by presenting one recent development in the field of near field imaging where a lensless
microscope is introduced. Its operation principle is based upon wavelength encoding of the spatial information through
non periodic holes array and right after decoding the spatial information using a spectrometer. In the second part of the
paper we demonstrate a remote super sensing technique allowing monitoring, from a distance, the glucose level in the
blood stream of a patient by tracking the trajectory of secondary speckle patterns reflected from the skin of the wrist.