Download or read book Spectroscopie laser d ions de terres rares et nouveaux mat riaux pour l optique written by Mohamed Bouazaoui and published by . This book was released on 2000 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book SPECTROSCOPIE DANS L ETAT EXCITE DES IONS TERRES RARES ND3 ET TM3 ET FONCTIONNEMENT LASER MULTILONGUEUR D ONDE DU YAG written by Nicolas Garnier and published by . This book was released on 1997 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'ENSEMBLE DES TRAVAUX PRESENTES DANS CETTE THESE A ETE REALISE DANS LE CADRE DU GROUPEMENT DE RECHERCHE MATERIAUX LASERS (GDR CNRS N 1148, THEME : CRITERE DE QUALITE). IL EST ISSU D'UNE COLLABORATION ENTRE LE LABORATOIRE TRAITEMENT DU SIGNAL ET INSTRUMENTATION, LE LABORATOIRE PHYSICO-CHIMIE DES MATERIAUX LUMINESCENTS ET LES ENTREPRISES CRISMATEC ET BM INDUSTRIE. CES TRAVAUX ONT CONDUIT A LA MISE EN OEUVRE DE DIFFERENTES TECHNIQUES EXPERIMENTALES PERMETTANT LA COMPREHENSION DE DIVERS PROCESSUS SE MANIFESTANT PAR UNE LIMITATION DE L'EFFET LASER DANS LES CRISTAUX DE YAG : ND#3#+ (Y#3AL#5O#1#2 : ND#3#+) ET YLF : ND#3#+ (YLIF#4 : ND#3#+). LE PREMIER ASPECT DE CES PROCESSUS EST LIE A L'ION DOPANT, CE SONT DES PROCESSUS INTRINSEQUES TELS QUE L'ABSORPTION DANS L'ETAT EXCITE ET L'ADDITION DE PHOTON PAR TRANSFERT D'ENERGIE CONDUISANT A UN DEPEUPLEMENT DU NIVEAU METASTABLE EMETTEUR DANS L'INFRAROUGE. NOUS AVONS MIS AU POINT DIFFERENTES EXPERIENCES A DEUX FAISCEAUX LASER SYNCHRONISES (POMPE, SONDE) PERMETTANT L'ETUDE DES TRANSITIONS DANS L'ETAT EXCITE TANT DU POINT DE VUE SPECTRAL QUE DES SECTIONS EFFICACES. DANS LE CAS DU YLF : ND#3#+, CES TECHNIQUES ONT PERMIS LA MISE EN EVIDENCE D'UN DOUBLE PROCESSUS D'ADDITION DE PHOTONS PAR TRANSFERT D'ENERGIE CONDUISANT A DES EMISSIONS VISIBLES ET ULTRAVIOLETTES FAISANT SUITE A UN POMPAGE INFRAROUGE AINSI QU'UNE DOUBLE ABSORPTION DANS L'ETAT EXCITE AUTOUR DE LA LONGUEUR D'ONDE LASER (1.05 M). NOUS AVONS PAR AILLEURS APPLIQUE CES TECHNIQUES A L'ETUDE DE TRANSITIONS D'ABSORPTION DANS L'ETAT EXCITE INTERVENANT DANS LE PROCESSUS D'AVALANCHE DE PHOTONS DANS L'ION THULIUM POUR DIFFERENTES MATRICES (Y#3AL#5O#1#2, YALO#3 ET Y#2O#3). LE SECOND ASPECT DE CES TRAVAUX, APPLIQUE AU YAG : ND#3#+, NOUS A CONDUIT A ENVISAGER L'INTERVENTION D'UN PROCESSUS EXTRINSEQUE A L'ION DOPANT LIE A LA FORMATION DE CENTRES COLORES APRES POMPAGE OPTIQUE. ON OBSERVE AINSI, APRES POMPAGE, LA DIMINUTION D'UNE BANDE D'ABSORPTION AUTOUR DE 250 NM N'APPARTENANT PAS A L'ION ND#3#+, L'APPARITION D'UNE BANDE D'ABSORPTION S'ETENDANT DEPUIS LE VISIBLE JUSQU'A L'INFRAROUGE CONDUISANT AINSI A L'AUGMENTATION DE L'ABSORPTION RESIDUELLE A LA LONGUEUR D'ONDE LASER (1.064 M), CETTE ABSORPTION RESIDUELLE ETANT MESUREE PAR UNE TECHNIQUE INTERFEROMETRIQUE SPECIALEMENT DEVELOPPEE A CET EFFET. LE PROCESSUS ENVISAGE EST LE CHANGEMENT DE VALENCE D'UNE IMPURETE (PROBABLEMENT DU FER) PAR PIEGEAGE D'UN ELECTRON LIBERE DANS LA MATRICE YAG SOUS L'EFFET DU RAYONNEMENT ULTRAVIOLET DES FLASHES DE POMPAGE, PROCESSUS PARTIELLEMENT REVERSIBLE, AVEC LA CREATION DE CENTRES ABSORBANTS SOUS FORTE INTENSITE DE POMPAGE (PHENOMENE A DEUX PHOTONS) ET ANNIHILATION (BLANCHIMENT) DE CES CENTRES SOUS FAIBLE INTENSITE DE POMPAGE (PHENOMENE A UN PHOTON). L'HYPOTHESE ACTUELLE, QUANT A LA NATURE DE CES CENTRES, SERAIT LIEE AU PROCESSUS D'OXYDO-REDUCTION : FE#3#+ + E#- FE#2#+. NOUS AVONS OBSERVE QUE CES CENTRES COLORES AVAIENT UNE INFLUENCE SUR L'ENERGIE EXTRAITE ET SUR LA THERMIQUE DES BARREAUX EN FONCTIONNEMENT LASER.

Download or read book Spectroscopie des l ments de transition et des l ments lourds dans les solides written by F. Gaume and published by . This book was released on 1977 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book SPECTROSCOPIE LASER DE FIBRES OPTIQUES MONOMODES DOPEES PAR DES IONS TERRES RARES written by JEAN FRANCOIS.. MARCEROU and published by . This book was released on 1989 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: LA CARACTERISATION PAR SPECTROSCOPIE LASER A UN ET DEUX PHOTONS DE VERRES ET DE FIBRES OPTIQUES MONOMODES DOPES PAR DES IONS TERRES-RARES TRIVALENTS DEBOUCHE SUR L'UTILISATION DE LA FLUORESCENCE DANS L'APPLICATION A DES CAPTEURS A FIBRE OPTIQUE CONTINUMENT SENSIBLES. AU COURS DE CE TRAVAIL, LE ROLE DU CONFINEMENT DE L'ENERGIE DANS CE MILIEU GUIDE A PERMIS DE METTRE EN EVIDENCE L'AMPLIFICATION LASER, EN PARTICULIER DANS L'INFRAROUGE VERS 1,54 MICRONS POUR L'ION ERBIUM. DES GAINS TRES IMPORTANTS ONT ETE MESURES A CETTE LONGUEUR D'ONDE, OUVRANT LA POSSIBILITE DE REALISER DES AMPLIFICATEURS POUR LES TELECOMMUNICATIONS

Download or read book Nouvelle m thode de chimie combinatoire pour l optimisation des propri t s spectroscopiques des ions terres rares laser Yb3 Er3 et Ho3 dans des fibres monocristallines de sesquioxydes r fractaires M2O3 M written by Laetitia Laversenne and published by . This book was released on 2002 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cette étude s'inscrit dans le cadre de la recherche de nouveaux matériaux laser monocristallins pompés par des iodes et émettent dans le domaine proche infra-rouge. Nous nous sommes intéressés plus particulièrement aux ions terres rares Yb3+, Er3+ et Ho3+ pour leurs émissions respectives autour de 1030 nm,1540 nm,et 2100 nm. Nous avons sélectionné les matrices hautement réfractaires (température de fusion >2200°C) Y2O3, Sc2O3, Lu2O3 et Gd2O3 intéressantes pour leur propriétés thermo-mécaniques et aussi pour leurs faibles énergies de phonons Ce mémoire a pour objet la croissance de fibres monocristallines par la technique de zone flottante L.H.P.G. (Laser Heated Pedestal Growth) et leur caractérisation chimique, structurale et spectroscopique. L'originalité de ce travail repose sur le développement d'une nouvelle méthodologie de chimie combinatoire, basée sur l'élaboration d'échantillons présentant un gradient de composition en ions luminescents contrôlé et réparti longitudinalement entre les deux extrémités de la fibre. La mise en corrélation du dosage chimique et de mesures physiques effectués sur la fibre évolutive permet la détermination rapide et exhaustive de l'influence de la composition sur les propriétés physiques du matériau. La technique se révèle particulièrement efficace dans le cas de l'étude des systèmes multiconstitués et notamment pour déterminer rapidement les limites des domaines monophasés des diagrammes d'équilibre. Elle est mise à profit pour l'étude de la dynamique des états excités des ions Yb3+, Er3+ et Ho3+ dans Y2O3 et pour l'optimisation du système codopé Y2O3 : Yb3+ -Er3+ émettant à 1540 nm. La technique combinatoire est adaptée à toute propriété mesurable ponctuellement et non destructive. Elle trouve de nombreuses applications en science des matériaux.

Download or read book Proceedings written by and published by . This book was released on 1973 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book How Glass Changed the World written by Seth C. Rasmussen and published by Springer Science & Business Media. This book was released on 2012-02-23 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: Glass production is thought to date to ~2500 BC and had found numerous uses by the height of the Roman Empire. Yet the modern view of glass-based chemical apparatus (beakers, flasks, stills, etc.) was quite limited due to a lack of glass durability under rapid temperature changes and chemical attack. This “brief” gives an overview of the history and chemistry of glass technology from its origins in antiquity to its dramatic expansion in the 13th century, concluding with its impact on society in general, particularly its effect on chemical practices.

Download or read book ICREEC 2019 written by Ahmed Belasri and published by Springer Nature. This book was released on 2020-06-10 with total page 659 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights peer reviewed articles from the 1st International Conference on Renewable Energy and Energy Conversion, ICREEC 2019, held at Oran in Algeria. It presents recent advances, brings together researchers and professionals in the area and presents a platform to exchange ideas and establish opportunities for a sustainable future. Topics covered in this proceedings, but not limited to, are photovoltaic systems, bioenergy, laser and plasma technology, fluid and flow for energy, software for energy and impact of energy on the environment.

Download or read book Nuclear Waste Conditioning written by France. Commissariat à l'énergie atomique (CEA) and published by Le Moniteur Editions. This book was released on 2009 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Re envisioning Remote Sensing Applications written by Ripudaman Singh and published by CRC Press. This book was released on 2023-09-25 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Re-envisioning Remote Sensing Applications: Perspectives from Developing Countries aims at discussing varied applications of remote sensing, with respect to upcoming technologies with varied themes like agricultural, soil and land degradation studies, hydrology, microclimates and climate change, land-use/land cover analysis, and so forth.

Download or read book Physics Briefs written by and published by . This book was released on 1993 with total page 1180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cathodoluminescence in Geosciences written by M. Pagel and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 518 pages. Available in PDF, EPUB and Kindle. Book excerpt: An up-to-date overview of cathodoluminescence microscopy and spectroscopy in the field of geosciences, including new important data on cathodoluminescence spectroscopy, physical parameters and systematic spectral analysis of doped minerals. Each chapter, written by a well-known specialist, covers classic and new fields of application such as carbonate diagenesis, silicates, brittle deformation in sandstones, gemstone recognition, biomineralization, economic geology or geochronology. Useful to all scientists, graduates and professional engineers throughout the geosciences community.

Download or read book Nanomaterials For Energy Conversion And Storage written by Dunwei Wang and published by World Scientific. This book was released on 2017-11-10 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of nanomaterials in energy conversion and storage represents an opportunity to improve the performance, density and ease of transportation in renewable resources. This book looks at the most recent research on the topic, with particular focus on artificial photosynthesis and lithium-ion batteries as the most promising technologies to date. Research on the broad subject of energy conversion and storage calls for expertise from a wide range of backgrounds, from the most fundamental perspectives of the key catalytic processes at the molecular level to device scale engineering and optimization. Although the nature of the processes dictates that electrochemistry is a primary characterization tool, due attention is given to advanced techniques such as synchrotron studies in operando. These studies look at the gap between the performance of current technology and what is needed for the future, for example how to improve on the lithium-ion battery and to go beyond its capabilities.Suitable for students and practitioners in the chemical, electrochemical, and environmental sciences, Nanomaterials for Energy Conversion and Storage provides the information needed to find scalable, economically viable and safe solutions for sustainable energy.

Download or read book Organic Solid State Lasers written by Sébastien Forget and published by Springer. This book was released on 2013-07-03 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic lasers are broadly tunable coherent sources, potentially compact, convenient and manufactured at low-costs. Appeared in the mid 60’s as solid-state alternatives for liquid dye lasers, they recently gained a new dimension after the demonstration of organic semiconductor lasers in the 90's. More recently, new perspectives appeared at the nanoscale, with organic polariton and surface plasmon lasers. After a brief reminder to laser physics, a first chapter exposes what makes organic solid-state organic lasers specific. The laser architectures used in organic lasers are then reviewed, with a state-of-the-art review of the performances of devices with regard to output power, threshold, lifetime, beam quality etc. A survey of the recent trends in the field is given, highlighting the latest developments with a special focus on the challenges remaining for achieving direct electrical pumping of organic semiconductor lasers. A last chapter covers the applications of organic solid-state lasers.

Download or read book Spark Plasma Sintering Current Status New Developments and Challenges written by Giacomo Cao and published by Elsevier. This book was released on 2019-06-17 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spark Plasma Sintering: Current Status, New Developments and Challenges: A Review of the Current Trends in SPS looks at the progress made in the field of SPS. It includes a review of the scientific mechanisms, materials synthesis and industry applications for this processing technique. Chapters are written by leading experts in the field, encompassing topics surrounding the densification mechanism and microstructure evolution, the classification of high-performance materials, a review of numerical simulation, discussions of new technology advances, such as HP-SPS, flash sintering and related challenges. This book will be useful for researchers, engineers and students within the materials science and engineering fields. Provides significant information on the most relevant research topics currently being addressed by the SPS community Highlights the application of SPS techniques Reviews critical issues that still need to be overcome when utilizing SPS technology

Download or read book The Physical Principles of Magneto optical Recording written by Masud Mansuripur and published by Cambridge University Press. This book was released on 1998-07-30 with total page 780 pages. Available in PDF, EPUB and Kindle. Book excerpt: First-time paperback of successful and well-reviewed book; for graduate students and researchers in physics and engineering.

Download or read book ZnO Thin Films written by Paolo Mele and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zinc oxide (ZnO) is an n-type semiconductor with versatile applications such as optical devices in ultraviolet region, piezoelectric transducers, transparent electrode for solar cells and gas sensors. This book "ZnO Thin Films: Properties, Performance and Applications" gives a deep insight in the intriguing science of zinc oxide thin films. It is devoted to cover the most recent advances and reviews the state of the art of ZnO thin films applications involving energy harvesting, microelectronics, magnetic devices, photocatalysis, photovoltaics, optics, thermoelectricity, piezoelectricity, electrochemistry, temperature sensing. It serves as a fundamental information source on the techniques and methodologies involved in zinc oxide thin films growth, characterization, post-deposition plasma treatments and device processing. This book will be invaluable to the experts to consolidate their knowledge and provide insight and inspiration to beginners wishing to learn about zinc oxide thin films.