Download or read book Optimisation de mat riaux dop s par les ions ytterbium pour applications laser de fortes puissances written by Pierre-Olivier Petit and published by . This book was released on 2010 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les lasers solides à base de monocristaux dopés par les ions ytterbium offrent un grand nombre d’avantages pour les applications laser de forte puissance ou en régime d’impulsions ultra-brèves. Les monocristaux d’aluminates, en particuliers Yb :CaGdAlO4 et Yb :YAlO3 sont des candidats très intéressants pour ces applications autour d’un micron. Nous avons cherché, dans le cadre de ce travail de thèse, à améliorer les qualités cristallines de ces matériaux en éliminant deux grandes familles de défauts présents : les centres colorés et les centres diffusants. Les monocristaux obtenus après traitement spécifique sont exempts de défauts et présentent des performances laser nettement supérieures. De plus, afin de tirer le meilleur partie des matériaux laser existants, une technique d’assemblage de matériaux par voie sol-gel a été développée. Des effets laser dans plusieurs matériaux hétéro-composites originaux ont été obtenus et des améliorations significatives de la thermique de ces systèmes ont été démontrés dans le cadre de ce travail
Download or read book Mat riaux lasers dop s l ion ytterbium written by Vanessa Cardinali and published by . This book was released on 2011 with total page 267 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dans les lasers, les gradients de température dans les milieux à gain provoquent des déformations de l'onde laser qui s'y propage. Le but de ma thèse est de mesurer les propriétés thermo-optiques (conductivité thermique, coefficient thermo-optique dn/dT, coefficient de dilatation) de nouveaux matériaux lasers permettant d'atteindre des énergies élevées à de hautes cadences de tir. Ces matériaux sont des céramiques sesquioxydes de scandium Sc2O3, de lutétium Lu2O3 et d'yttrium Y2O3 dopées ytterbium. Les mesures se font à basse température (température de l'azote liquide, 77 K) car les propriétés thermiques sont améliorées lorsque la température du matériau diminue. Ces matériaux ont également été testés en configuration d'oscillateur laser relaxé, montrant ainsi tout l'intérêt de travailler à basse température. Les mesures de ces propriétés représentent un enjeu majeur pour le développement des lasers de forte puissance, d'autant plus que les données de la littérature concernant ces matériaux, dans ces domaines de température, sont quasiment inexistantes. D'autres matériaux comme des cristaux et des céramiques de YAG, des cristaux de fluorure de calcium CaF2 dopés ytterbium, et des verres phosphates dopés néodyme ont également été testés.
Download or read book Nouveaux mat riaux laser dop s l ytterbium written by Sébastien Chénais and published by . This book was released on 2002 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ce travail concerne l'étude de nouveaux cristaux dopés à l'ion ytterbium, pour le développement de lasers efficaces (et éventuellement accordables) émettant vers 1 ~. La première partie traite des performances laser en pompage par diode de forte puissance (1 0-15 ~ de nouveaux cristaux: 1'Yb:GGG, l'Yb:'GdCOB, 1'Yb:BOYS (et 1'Yb:CaBOYS), 1'Yb:SYS et 1'Yb:YSO. L'efficacité, l'accordabilité, et le comportement thermique de ces matériaux est discutée, et quelquefois illustrée par une comparaison entre matériaux voisins. Les effets thermiques limitent la montée en puissance dans la plupart de ces nouveaux matériaux: leur étude détaillée fait l'objet de la seconde partie. Nous commençons par une synthèse théorique sur les effets thermiques et thermomécaniques dans les lasers solides. Après une description des différentes méthodes expérimentales d'investigation des effets thermiques, nous décrivons le banc de mesure que nous avons mis en place. Il est basé sur un analyseur de front d'onde de Shack-Hartmann, et il permet la mesure des lentilles fuermiques (et de leurs aberrations) dans des configurations de pompage longitudinal, en présence (ou non) d'effet laser. Nous décrivons les caractéristiques et les limitations de cet outil en détail. Des mesures de lentilles thermiques sont ensuite rapportées, pour la première fois, dans des matériaux dopés à l'ytterbium. Nous avons mis en évidence d'importants effets non radiatifs qui contribuent à la charge thermique, contrairement à ce qui est généralement admis. Nous détaillons alors comment, avec un modèle analytique simple, on peut déduire de ces mesures le rendement quantique et le coefficient thermo-optique des matériaux considérés. Nous avons également mis en évidence expérimentalement l'influence de la longueur d'onde laser sur la charge thermique, la réduction des effets thermiques dans des cristaux composites, ou encore la contribution significative de l'effet photoélastique à la lentille thermique dans 1'Yb:GdCOB.
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 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 Handbook of Solid State Lasers written by B Denker and published by Elsevier. This book was released on 2013-02-20 with total page 688 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solid-state lasers which offer multiple desirable qualities, including enhanced reliability, robustness, efficiency and wavelength diversity, are absolutely indispensable for many applications. The Handbook of solid-state lasers reviews the key materials, processes and applications of solid-state lasers across a wide range of fields.Part one begins by reviewing solid-state laser materials. Fluoride laser crystals, oxide laser ceramics, crystals and fluoride laser ceramics doped by rare earth and transition metal ions are discussed alongside neodymium, erbium and ytterbium laser glasses, and nonlinear crystals for solid-state lasers. Part two then goes on to explore solid-state laser systems and their applications, beginning with a discussion of the principles, powering and operation regimes for solid-state lasers. The use of neodymium-doped materials is considered, followed by system sizing issues with diode-pumped quasi-three level materials, erbium glass lasers, and microchip, fiber, Raman and cryogenic lasers. Laser mid-infrared systems, laser induced breakdown spectroscope and the clinical applications of surgical solid-state lasers are also explored. The use of solid-state lasers in defense programs is then reviewed, before the book concludes by presenting some environmental applications of solid-state lasers.With its distinguished editors and international team of expert contributors, the Handbook of solid-state lasers is an authoritative guide for all those involved in the design and application of this technology, including laser and materials scientists and engineers, medical and military professionals, environmental researchers, and academics working in this field. - Reviews the materials used in solid-state lasers - Explores the principles of solid-state laser systems and their applications - Considers defence and environmental applications
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 Advances in Spectroscopy for Lasers and Sensing written by Baldassare Di Bartolo and published by Springer Science & Business Media. This book was released on 2006-07-21 with total page 574 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents the Proceedings of "New Development in Optics and Related Fields," held in Italy in June, 2005. This meeting was organized by the International School of Atomic and Molecular Spectroscopy of the "Ettore Majorana" Center for Scientific Culture. The purpose of this Institute was to provide a comprehensive and coherent treatment of the new techniques and contemporary developments in optics and related fields.
Download or read book Persistent Phosphors written by Jianrong Qiu and published by Woodhead Publishing. This book was released on 2020-11-24 with total page 309 pages. Available in PDF, EPUB and Kindle. Book excerpt: Persistent Phosphors: From Fundamentals to Applications provides an introduction to the key synthesis methods, characterization methods, physical mechanisms, and applications of this important luminescent materials system. The book covers basic persistent phosphorescence, introducing concepts such as emission, luminescence, phosphorescence, persistent phosphorescence and the development of persistent phosphors. Then, synthesis methods are reviewed and the connections between synthesis methods and improved materials properties are discussed. Characterization methods to investigate the trapping and de-trapping mechanism are also presented. Other sections cover the theoretical framework and energy band engineering models and materials with a focus on activators, hosts, emission bands and excitation bands. Finally, the most relevant applications of persistent phosphors are included for use in displays, safety signs, bio-labels and energy. Persistent Phosphors is an invaluable reference for materials scientists and engineers in academia and R&D. It is a key resource for chemists and physicists. - Presents characterization techniques to reveal the photophysical and photochemical properties of defects for this important category of luminescent materials - Discusses the structural role of defects in polycrystals and the capture-storing-migration-release progress of excited carriers - Demonstrates the synthesis routes and potential applications for persistent phosphor materials
Download or read book Crystal Field Analysis written by Nicolae Avram and published by . This book was released on 2008-08 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Glass Nanocomposites written by Basudeb Karmakar and published by William Andrew. This book was released on 2016-01-19 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt: Glass Nanocomposites: Synthesis, Properties and Applications provides the latest information on a rapidly growing field of specialized materials, bringing light to new research findings that include a growing number of technologies and applications. With this growth, a new need for deep understanding of the synthesis methods, composite structure, processing and application of glass nanocomposites has emerged. In the book, world renowned experts in the field, Professors Karmakar, Rademann, and Stepanov, fill the knowledge gap, building a bridge between the areas of nanoscience, photonics, and glass technology. The book covers the fundamentals, synthesis, processing, material properties, structure property correlation, interpretation thereof, characterization, and a wide range of applications of glass nanocomposites in many different devices and branches of technology. Recent developments and future directions of all types of glass nanocomposites, such as metal-glasses (e.g., metal nanowire composites, nanoglass-mesoporous silica composites), semiconductor-glass and ceramic-glass nanocomposites, as well as oxide and non-oxide glasses, are also covered in great depth. Each chapter is logically structured in order to increase coherence, with each including question sets as exercises for a deeper understanding of the text. - Provides comprehensive and up-to-date knowledge and literature review for both the oxide and non-oxide glass nanocomposites (i.e., practically all types of glass nanocomposites) - Reviews a wide range of synthesis types, properties, characterization, and applications of diverse types of glass nanocomposites - Presents future directions of glass nanocomposites for researchers and engineers, as well as question sets for use in university courses
Download or read book Handbook on Borates written by M. P. Chung and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Boron is a naturally-occurring element. It is typically combined with other substances to form borates, including boric acid, salts of borates, and boron oxide. Boron is released naturally into the environment by oceans, volcanoes, and geothermal steam. It is also mined and used by many industries. Borates are used largely to produce glass. Boric acid is used in flame retardants, medicines, pesticides, and wood preservatives. Low-dose exposure can cause respiratory and skin irritation, vomiting, diarrhoea, nausea, and headaches. Borates have not been thoroughly tested for health effects in humans, but the EPA has found potential developmental toxicity (especially on the testes). Borates are considered safer to human health and the environment than other flame retardants (like PBDEs and PCBs) and wood preservatives (like arsenic). This new and important book gathers the latest research from around the globe in the study of borates with a focus on such topics as: boron-based wood preservatives and their uses, molecular aspects of boron treatment technologies, alkaline earth borates, borate toxicity and effect on drug stability and others.
Download or read book Specialty Optical Fibers Handbook written by Alexis Mendez and published by Elsevier. This book was released on 2011-10-10 with total page 841 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a comprehensive contributed volume that aims to describe and explain the design, fabrication, operating characteristics, and specific applications of the most popular and useful types of specialty optical fibers. These "specialty fibers include any kind of optical fiber that has been architecturally manipulated to diverge from a conventional structure. For instance, metal-coated fibers can be utilized for bandwidth improvement, and hollow core fibers offer more controllable dispersion for sensitive medical procedures. Applications for these specialty fibers abound in the biomedical, sensors, and industrial fields, as well as in more traditional communications capacities. This book will act as a specialty fiber "guided tour, hosted by the top names in the discipline. The globally renowned editors, Drs. Mendez and Morse, have extensive experience in research, academia, and industry.*Completely covers biomedical and industrial sensor technology with emphasis on real world applications *Comparative studies of pros and cons of all fiber types with relation to test and measurement, mechanical properties and strength, and reliability*Easy to access essential facts and details at the begining of each chapter
Download or read book Rare Earth Elements and Their Minerals written by Michael Aide and published by BoD – Books on Demand. This book was released on 2020-06-17 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the recent evolution of rare earth elements and their mineralogy, both natural and synthetic analogues. Authors review and document rare earth element chemistry in the aqueous environment and the petrology of the rare earth element-bearing mineral Allanite. Synthetic rare earth minerals and their applications is a rapidly evolving discipline important to medicine, advanced digital technologies, and solid-state physics. Authors report on the synthesis of a macrocyclic gadolinium complex and also gadolinium complexes and their applications in medicine. Authors present compelling advances in gadolinium isotopes and oxides as substrates for induced excitation and luminescent material sciences.
Download or read book Doped Nanomaterials and Nanodevices Luminescence and applications written by Wei Chen and published by . This book was released on 2010 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt:
