Download or read book Conversion de lumi re dans l infrarouge moyen par amplification fibr e written by Jean‐Christophe Gauthier and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Motivé par le fort potentiel scientifique et technologique de l'infrarouge moyen (3-20 μm), le développement de sources lumineuses intenses dans cette région du spectre électromagnétique a subi un essor considérable depuis le début des années 2000. On retrouve maintenant une grande variété de lasers et autres sources pouvant émettre au-delà de 3 μm (lasers à fibres, lasers à cascade quantique, systèmes de conversion paramétrique, lasers à l'état solide, etc). Toutefois, malgré la panoplie d'options ayant émergées pour tester les nouvelles possibilités offertes par l'infrarouge moyen, plusieurs défis restent encore à relever au niveau des sources. Notamment, les enjeux de couverture spectrale, d'efficacité et de simplicité d'utilisation et de fabrication des sources sont encore omniprésents. À titre d'exemple, peu de lasers peuvent produire des impulsions courtes (sub-picosecondes) dans l'infrarouge moyen, et seuls les plus complexes et coûteux d'entre eux peuvent accorder ces impulsions sur une grande plage spectrale, s'accompagnant d'une efficacité énergétique globale très faible. D'autre part, ces problèmes de couverture spectrale, de simplicité et d'efficacité se retrouvent également chez les sources supercontinuum utilisées pour les applications requérant un spectre large couvrant en totalité ou en partie la région de 3 à 5 μm, qui contient de nombreuses résonances moléculaires utiles en spectroscopie (hydrocarbones et oxydes simples). Bien que ces sources produisent un spectre très large à partir d'un système tout fibre et des puissances moyennes pouvant atteindre plusieurs Watts, elles ont le désavantage de générer une grande proportion de leur énergie en-deçà de 3 μm (habituellement entre 40 et 90%), de produire un spectre peu uniforme, et ont beaucoup de difficulté à couvrir la totalité de la fenêtre de 3 à 5 μm. Constatant ces défis, l'objectif global de cette thèse était de faciliter et d'améliorer la conversion et la génération de spectre dans la région de 3 à 5 μm. Comme première contribution de cette thèse, une nouvelle méthode de génération de supercontinuum a été démontrée, permettant la création d'un spectre plat allant de 2.6 à 4.1 μm à partir d'un système simple et produisant jusqu'à 82% de l'énergie spectrale au-delà de 3 μm (Chapitre 2). En poursuivant avec cette approche, il a été possible d'établir un record pour le supercontinuum le plus large généré dans une fibre de fluoroindate (InF3), allant de 2.4 à 5.4 μm (Chapitre 3). Les chapitres 4 et 5 avaient pour objectif d'approfondir notre connaissance et d'optimiser les paramètres expérimentaux de cette technique. Finalement, la contribution présentée dans le chapitre 6 a permis de s'attaquer au problème de la disponibilité d'impulsions brèves et accordables dans l'infrarouge moyen à partir de sources plus abordables et pratiques à utiliser que les chaînes lasers à conversion paramétrique. Pour ce faire, nous avons utilisé les phénomènes de fission solitonique et d'autodécalage Raman afin de décaler spectralement et de manière contrôlée des impulsions femtosecondes entre 2.8 μm et 4.8 μm, le tout à partir d'un système fibré.
Download or read book Etude de la conversion de fr quence par amplification param trique dans les fibres optiques transparentes dans l infrarouge written by Claire Alhenc-Gelas and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: De nombreuses applications militaires ou civiles, telles que la spectroscopie dans les bandes de transmission de l'atmosphère (bandes 3-5μm et 8-12μm), nécessitent de disposer de sources émettant dans le moyen infrarouge (IR). Les travaux de cette thèse portent sur la génération de rayonnement dans la bande 3-5μm par amplification paramétrique (mélange à quatre ondes) dans les fibres optiques en verres fluorés et en verres de chalcogénures. La première partie de ce travail a été consacrée à l'étude théorique et à la modélisation des conditions d'accord de phase et du gain paramétrique dans des fibres à saut d'indice monomodes en verres fluorés ZBLAN et verres de chalcogénures As2S3 et As2Se3. La nature des résultats obtenus nous a conduit à étudier théoriquement le potentiel de l'accord de phase multimode dans les fibres en verres de chalcogénures. La deuxième partie de ce travail a porté sur la modélisation de l'amplification paramétrique dans des fibres en verres de chalcogénures microstructurées à géométrie hexagonale. Pour ce faire, un modèle simplifié de la propagation dans les fibres microstructurées hexagonales a été développé : le modèle de l'indice effectif de gaine (EIM). Il a ensuite été comparé à une méthode de résolution aux éléments finis. Grâce à cette comparaison, nous avons pu améliorer la précision du modèle EIM en déterminant la valeur de plusieurs paramètres empiriques. Ce modèle nous a alors permis de prédire l'efficacité du processus d'amplification paramétrique dans les fibres microstructurées. L'ensemble de ces études théoriques a permis d'identifier les fibres les plus adaptées à la conversion de fréquence vers la bande 3-5μm. Enfin, nous avons réalisé un banc de mesure de la dispersion chromatique des fibres, ainsi que le dimensionnement d'un convertisseur de fréquence utilisant les fibres identifiées dans l'étude théorique.
Download or read book Quantum Mechanics Volume 3 written by Claude Cohen-Tannoudji and published by John Wiley & Sons. This book was released on 2019-12-16 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new, third volume of Cohen-Tannoudji's groundbreaking textbook covers advanced topics of quantum mechanics such as uncorrelated and correlated identical particles, the quantum theory of the electromagnetic field, absorption, emission and scattering of photons by atoms, and quantum entanglement. Written in a didactically unrivalled manner, the textbook explains the fundamental concepts in seven chapters which are elaborated in accompanying complements that provide more detailed discussions, examples and applications. * Completing the success story: the third and final volume of the quantum mechanics textbook written by 1997 Nobel laureate Claude Cohen-Tannoudji and his colleagues Bernard Diu and Franck Laloë * As easily comprehensible as possible: all steps of the physical background and its mathematical representation are spelled out explicitly * Comprehensive: in addition to the fundamentals themselves, the books comes with a wealth of elaborately explained examples and applications Claude Cohen-Tannoudji was a researcher at the Kastler-Brossel laboratory of the Ecole Normale Supérieure in Paris where he also studied and received his PhD in 1962. In 1973 he became Professor of atomic and molecular physics at the Collège des France. His main research interests were optical pumping, quantum optics and atom-photon interactions. In 1997, Claude Cohen-Tannoudji, together with Steven Chu and William D. Phillips, was awarded the Nobel Prize in Physics for his research on laser cooling and trapping of neutral atoms. Bernard Diu was Professor at the Denis Diderot University (Paris VII). He was engaged in research at the Laboratory of Theoretical Physics and High Energy where his focus was on strong interactions physics and statistical mechanics. Franck Laloë was a researcher at the Kastler-Brossel laboratory of the Ecole Normale Supérieure in Paris. His first assignment was with the University of Paris VI before he was appointed to the CNRS, the French National Research Center. His research was focused on optical pumping, statistical mechanics of quantum gases, musical acoustics and the foundations of quantum mechanics.
Download or read book New Developments in Ophthalmology Nijmegen 16 18 October 1975 written by A.F. Deutman and published by Springer. This book was released on 1976-06-30 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: Symposium held at Nijmegen, The Netherlands, October 16-18, 1975
Download or read book Dictionary of Building and Civil Engineering written by Don Montague and published by Taylor & Francis. This book was released on 1996 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dual-language dictionary lists over 20,000 specialist terms in both French and English, covering architecture, building, engineering and property terms. It meets the needs of all building professionals working on projects overseas. It has been comprehensively researched and compiled to provide an invaluable reference source in an increasingly European marketplace.
Download or read book Livestock Policy Analysis written by International Livestock Research Institute and published by ILRI (aka ILCA and ILRAD). This book was released on 1995-01-01 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: Policy concepts; Identification of policy issues; Production systems, supply and demand; Market, price and trade policies; Marketing and distribution systems; Budget and manpower planning; Land tenure police for the livestock sector; Policy analysis report writing and communication; Livestock production and marketing in alphabeta - a case study.
Download or read book Advanced Signal Processing and Digital Noise Reduction written by Saeed V. Vaseghi and published by Vieweg+Teubner Verlag. This book was released on 1996-05 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bayesian Estimation and classification. Hidden markov models. Wiener filters. Kalman and adaptive least squared error filters.
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 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 Confocal Microscopy and Multiphoton Excitation Microscopy written by Barry R. Masters and published by SPIE Press. This book was released on 2006 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text guides you through the principles and practical techniques of confocal and multiphoton microscopy. It also describes the historical connections and parallel inventions that resulted in modern techniques of live cell imaging and their use in biology and medicine. You will find comparisons of different types of confocal and multiphoton microscopes, solutions to the problems one would encounter when using various microscopic techniques, tips on selecting equipment, and an extensive annotated bibliography of additional resources.
Download or read book Handbook of Fiber Optic Data Communication written by and published by Academic Press. This book was released on 2002-04-13 with total page 843 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Handbook includes chapters on all the major industry standards, quick reference tables, helpful appendices, plus a new glossary and list of acronyms. This practical handbook can stand alone or as a companion volume to DeCusatis: Fiber Optic Data Communication: Technological Advances and Trends (February 2002, ISBN: 0-12-207892-6), which was developed in tandem with this book.* Includes emerging technologies such as Infiniband, 10 Gigabit Ethernet, and MPLS Optical Switching* Describes leading edge commercial products, including LEAF and MetroCore fibers, dense wavelength multiplexing, and Small Form Factor transceiver packages* Covers all major industry standards, often written by the same people who designed the standards themselves* Includes an expanded listing of references on the World Wide Web, plus hard-to-find references for international, homologation, and type approval requirements* Convenient tables of key optical datacom parameters and glossary with hundreds of definitions and acronyms* Industry buzzwords explained, including SAN, NAS, and MAN networking* Datacom market analysis and future projections from industry leading forecasters
Download or read book Experimental Chaos written by Stefano Boccaletti and published by A I P Press. This book was released on 2004-12-14 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 8th Experimental Chaos Conference again demonstrated the broad spectrum of areas where nonlinear dynamics plays an important role, such as circuits, hydrodynamics, optics, chemistry, fracture dynamics, neuroscience, and cognitive science. Additional contributions outline the trends for development and application of concepts and techniques of nonlinear dynamics.
Download or read book Critical Technologies Plan written by and published by . This book was released on 1989 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pandex Current Index to Scientific and Technical Literature written by and published by . This book was released on 1969 with total page 1778 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laser 50 Years Of Discoveries written by Fabien Bretenaker and published by World Scientific. This book was released on 2014-10-27 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique book provides an overview of the principle and applications of lasers enriched with numerous illustrations.Being over fifty years old, lasers continue to amaze us. Their performance characteristics are constantly reaching new limits, and the scope of their applications continues to expand. Yet, it took years of effort by teams of physicists to transform the fundamental notions of Einstein into the first experimental beam of laser light. And history is still going on as fundamental research is now triggered by its remarkable properties.This book addresses every aspects of laser light, from its fundamental principles to its industrial applications, at a level particularly suited for high school teachers, students, and anybody curious about science and technology.
Download or read book Photoacoustic and Photothermal Phenomena written by Peter Hess and published by Springer. This book was released on 2014-03-12 with total page 575 pages. Available in PDF, EPUB and Kindle. Book excerpt: photoacoustic and Photothermal Phenomena contains reviews and a large numberof selected contributed papers reporting progress in the application of new photoacoustic and photo- thermal techniques in physics, chemistry, biology, medicine and materials science. Theoretical and experimental work is presented on spectroscopy, kinetics and relaxation, trace analysis, mass and heat transport, surfaces and thin films, nondestructive evaluation,ultrasonics and semiconductors.
Download or read book NATO Glossary of Terms and Definitions written by North Atlantic Treaty Organization and published by CreateSpace. This book was released on 2013-03-08 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: NATO Glossary of terms and definitions (English and French). Listing terms of military significance and their definitions for use in NATO.
