Photonic-based multi-wavelength sensor for object identification

A Photonic-based multi-wavelength sensor capable of discriminating objects is proposed and demonstrated for intruder detection and identification. The sensor uses a laser combination module for input wavelength signal multiplexing and beam overlapping, a custom-made curved optical cavity for multi-beam spot generation through internal beam reflection and transmission and a high-speed imager for scattered reflectance spectral measurements. Experimental results show that five different wavelengths, namely 473nm, 532nm, 635nm, 670nm and 785nm, are necessary for discriminating various intruding objects of interest through spectral reflectance and slope measurements. Objects selected for experiments were brick, cement sheet, cotton, leather and roof tile

Multi-wavelength laser scanning architecture for object discrimination

A novel method for identifying and discriminating various objects using five different lasers is described. This method uses a laser combination module that allows five laser diodes of different wavelengths to sequentially emit identically polarized light beams through a common aperture, along one optical path. Each laser beam enters a custom-made curved optical cavity for multi-beam spot generation through internal partial beam reflection. The intensity of the reflected light beams from each spot is detected by a high-speed area scan image sensor. Object discrimination based on analyzing the Gaussian profile of reflected laser light at distinguishing wavelengths is demonstrated

Multi-Wavelength Laser Sensor for Intruder Detection and Discrimination

An intruder detection and discrimination sensor with improved optical design is developed using lasers of different wavelengths to demonstrate the concept of discrimination over a distance of 6 m. A distinctive feature of optics is used to provide additional transverse laser beam scanning. The sample objects used to demonstrate the concept of discrimination over a distance of 6 m are leaf, bark, black fabric, PVC, wood and camouflage material. A camouflage material is chosen to illustrate the discrimination capability of the sensor. The sensor utilizes a five-wavelength laser combination module, which sequentially emits identically-polarized laser light beams along one optical path. A cylindrical quasi-optical cavity with improved optical design generates multiple laser light beams for each laser. The intensities of the reflected light beams from the different spots are detected using a high speed area scan image sensor. Object discrimination and detection is based on analyzing the Gaussian profile of reflected light at the different wavelengths. The discrimination between selected objects is accomplished by calculating four different slopes from the objects\u27 reflectance spectra at the wavelengths 473 nm, 532 nm, 635 nm, 670 nm and 785 nm. Furthermore, the camouflage material, which has complex patterns within a single sample, is also detected and discriminated over a 6 m range by scanning the laser beam spots along the transverse direction. -------------------------------------------------------------------------------

A new vibrational technique for measurement of stress variations in thin films

A survey of thin films deposited by standard techniques (electrodeposition, chemical deposition, sputtering, physical deposition, etc.) shows that internal stress is a common problem, particularly in industrial applications. The presence of stress influences the properties of the film and when severe may cause the film to buckle or crack. There is a significant technological and industrial interest in measurements that determine the magnitude of the internal stress. Stress measurement represents a highly sensitive tool for the study of thin film structure in a non-destructive manner. Accurate measurements of the intemal stress in thin films is rather difficult and a number of methods have been described in the literature. This thesis describes a simple all-optical technique for measurement of internal stress in thin films deposited in a vacuum system. The technique is based on a measurement of changes in the modal resonant vibrational frequencies of the substrate/film structure which are caused by stress-induced changes in curvature. The modal vibrations are induced by photothermoelastic bending produced using low-power modulated laser diode light. The vibrational resonant frequency changes are monitored by a sensitive fibre optic interferometer system. A feedback system can allow direct readout of stress-related frequency variations with time as films are deposited or modified by processes such as exposure to the atmosphere. The technique was tested using chromium and magnesium fluoride thin films deposited on glass substrates

Non-contact Laser Spectroscopy for Plant Discrimination in Terrestrial Crop Spraying

The early development of a novel micro-photonic based sensing architecture for use in selective herbicide spraying systems performing noncontact spectral reflectance measurements of plants and soil in real time has been described. A combination module allows three laser diodes of different wavelengths to sequentially emit identically polarized light beams through a common aperture, along one optical path. Each exiting beam enters an optical structure which generates up to 14 parallel laser beams. A pair of combination modules and optical structures generates 28 beams over a 420mm span which illuminates the plants from above. The intensity of the reflected light from each spot is detected by a high speed line scan image sensor. Plant discrimination is based on analyzing the Gaussian profile of reflected laser light at distinguishing wavelengths. Two slopes in the spectral response curves from 635nm to 670nm and 670nm to 785nm are used to discriminate different plants. Furthermore, by using a finely spaced and collimated laser beam array, instead of an un-collimated light source, detection of narrow leaved plants with a width greater than 20mm is achievable

Contribution à l'étude du cuivre dans le silicium et d'une technique de caractérisation associée

Le cuivre est un contaminant majeur du silicium, connu pour être à l'origine de défaillances de composants intégrés. Son introduction dans les composants submicroniques engendre un risque supplémentaire de contamination et de fait accentue le besoin d'outils pour la détection du cuivre à l'état de trace dans le silicium. Cette thèse a pour but d'étudier les propriétés physiques du cuivre dans le silicium en utilisant la technique TID (pour Transient Ion Drift) comme outil de détection.Le chapitre I expose le comportement des impuretés métalliques en particulier le cuivre dans le silicium et les enjeux technologiques quant à la détection du cuivre à l'état de trace. Une description de la méthode utilisée dans ce travail a été détaillée dans le deuxième chapitre. L'optimisation de la cinétique d'activation, étape thermique nécessaire avant toute mesure TID, pour minimiser le risque de contamination supplémentaire a fait l'objet du troisième chapitre. Le chapitre IV a été consacré à l'étude du comportement du cuivre interstitiel sous l'effet de la lumière visible. Des modèles théoriques à l'appuis ont été utilisés pour expliquer les différents résultats obtenus. La dernière partie du manuscrit a été consacrée à l'étude du comportement du cuivre dans le silicium de type FZ (Fusion de Zone).Copper is well known to be a major contaminant in silicon and may cause electronic device failures. The recent introduction of copper interconnects into the silicon device technology enhance risk for copper contamination and a need for the development of highly sensitive and flexible detection tools. The aim of this thesis is to study the physical properties of copper in silicon using Transient Ion Drift (TID).Chapter I introduce a metallic impurities behavior in silicon and review recent results on copper in silicon, which are related to the field of copper trace detection. Transient Ion Drift method was detailed in the second chapter. The optimization of copper activation kinetics, necessary thermal stage before TID measurement, to minimize the additional risk of contamination was covered in the third chapter. Chapter IV investigates the influence of an exposure to visible light on interstitial copper. Theoretical models were used to explain the various results obtained. The last part of the manuscript will be focused on the copper behavior in Flow Zone silicon.STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

L' Outsourcing ou externalisation dans l'industrie pharmaceutique

LYON1-BU Santé (693882101) / SudocSudocFranceF

Synthèse et étude de 3'-desoxy-3'-C-methylnucléosides pyrimidiques

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF