Hyper-sensitive plasmonic optical system for pollutant detection

The detection of micro pollutants by new innovative systems is one of the important issues of our society. This study is dedicated to innovative pollutant sensors exploiting the interaction properties between light and original nanostructured materials, in order to create a real jump in performance in terms of detection limit, quantification and sensitivity. The detection of our pesticide is based on the variation of the optical properties of the materials used in the presence of the molecule to be detected. We propose two ways of investigation that are (i) the Surface Plasmon Resonance detection (SPR) in Kretschmann configuration and (2) the use of an original functionalized nano structured organization based on the use of functionalized gold nanoparticles

Innovative fiber optic sensor for hydrogen detection

A new design of a fiber optic sensor using Palladium as a sensitive layer is presented. In this new configuration, a transducer layer is deposited on a multimode fiber (without the optical cladding). The transducer layer is a multilayer stack based on a silver, a silica and a Pd layer. The spectral modulation of the light transmitted by the fiber allows to detect hydrogen. The sensor is only sensitive to the Transverse Magnetic polarized light and the Transverse Electric polarized light can be used as a reference signal. The multilayer thickness defines the sensor performance. The Silica thickness tunes the resonant wavelength, whereas the silver and Pd thickness determines the sensor sensitivity. We present some results obtained for different multilayer Pd configuration

Detailed spectral monitoring of different combustible blends based on gasoline, ethanol and methanol using FT-Raman spectroscopy

The use of mixtures of oil-based fuels with organic chemical components (e.g. ethanol, methanol) has been gaining ground in recent years. Several countries try nowadays to replace part of the fossil fuels for various reasons including economics, sustainability or optimization of resources. The characteristics of these combustiblerelated chemical component blends can be analyzed by different means. Optical spectral analysis (e.g. Raman, Fourier-transforminfrared, etc.) can extract inmany casesmost of the required information concerning themolecular structure of a determined chemical sample in an effective and clean manner. Experimental detailed Raman spectra fromvarious gasoline-ethanol blends and a gasoline-ethanolmethanol blend are presented. The Raman spectral information obtained has been used for approximated quantitative analysis with no additional chemical marker or complicated calibration methods. The analysis has been performed using a self-designed, low-cost, robust and frequency precise Fourier transform Raman (FT-Raman) spectrometer. This proposed FT-Raman spectrometer has been constructed with a Michelson interferometer, an in-house designed photon counter, and a sensitive trans-impedance photo-detector. Additional complex hardware was not used to compensate the mechanical or thermal drifts disturbances in the interferometer. For accurate spectral calculation an interference pattern generated by a low-power Helium-Neon laser (wavelength λ=632.816nm)was used. The resulting spectral data are in the range of 0*cm-1 to 3500*cm-1. The resolution of these Raman spectra is 1.66*cm-1. Higher resolutions are possible since the scanning distances in the Michelson interferometer can be extended substantially before instrumental effects appear. A comparison of the experimental results obtained with standard Raman shift values revealed a satisfactory accuracy and precision in frequency detection