Download or read book CONTRIBUTION A L ETUDE DES CHAMPS THERMIQUES ET ELECTRIQUES DANS LES LASERS SEMI CONDUCTEURS written by VALERIE.. LEPALUDIER and published by . This book was released on 1995 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: CETTE RECHERCHE CONCERNE L'ETUDE MICROTHERMIQUE DES LASERS SEMI-CONDUCTEURS A DISSIPATION THERMIQUE NON UNIFORMEMENT DISTRIBUEE. ELLE PORTE SUR LE DEVELOPPEMENT DE MODELES THEORIQUES ET DE METHODES DE CARACTERISATION THERMIQUE SPECIFIQUES. LA MISE AU POINT ET LE DEVELOPPEMENT DE CES METHODES SONT REALISES SUR LES LASERS MULTIJONCTIONS A DOUBLE HETEROSTRUCTURE DE TYPE GAALAS/GAAS. UNE MODELISATION DES CHAMPS THERMIQUES, FONDEE SUR L'UTILISATION COMBINEE DE TRANSFORMATIONS INTEGRALES A ETE MISE EN UVRE. ELLE PERMET D'ETUDIER FINEMENT LES PHENOMENES DE CONSTRICTION ET D'ANALYSER LES INTERACTIONS ENTRE LES DIFFERENTES SOURCES DE CHALEUR. L'EXPLOITATION DU MODELE MET EN EVIDENCE LE ROLE DES CARACTERISTIQUES LES PLUS SENSIBLES POUR LES REGIMES THERMIQUES STATIONNAIRE ET INSTATIONNAIRE (QUALITE DU REPORT DU COMPOSANT, METALLISATION DE LA COUCHE DE CONTACT). LE MODELE HYBRIDE A ETE CONFRONTE A UN MODELE AUX ELEMENTS FINIS. UNE METHODE DE MESURE DE TEMPERATURE EST PROPOSEE. ELLE EST FONDEE SUR LA DETECTION, APRES COUPURE DE L'ALIMENTATION DU LASER, DE LA DIFFERENCE DE POTENTIEL ELECTRIQUE DE CONTACT, CONSECUTIVE A L'INJECTION DE FAIBLE COURANT, ET DE SA THERMODEPENDANCE. LA CONTRIBUTION DE L'EFFET THERMOELECTRIQUE EST ANALYSEE FINEMENT AU MOYEN D'UN MODELE DE COUPLAGE BIDIMENSIONNEL. CE TRAVAIL PERMET D'OBTENIR DES EVOLUTIONS DE TEMPERATURE AU COURS DE COMMUTATIONS DE QUELQUES MICROSECONDES A QUELQUES MILLISECONDES. EN OUTRE, L'ANALYSE DES THERMOGRAMMES EXPERIMENTAUX CORRESPONDANT AU REFROIDISSEMENT CONSECUTIF A UNE COUPURE D'ALIMENTATION DE 100 MS PERMET DE DETERMINER LA TEMPERATURE DE JONCTION CORRESPONDANT AU REGIME STATIONNAIRE, AINSI QU'UNE CARACTERISATION THERMIQUE IN-SITU DU COMPOSANT (DIFFUSIVITE THERMIQUE DU SUBSTRAT, RESISTANCE THERMIQUE D'INTERFACE ENTRE LE LASER ET LE PLOT DIFFUSEUR)
Download or read book Contribution l tude des propri t s spectrales et spatiales des lasers semi conducteurs en cavit externe microforme written by Sylvain Mailhot and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 1996 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book CONTRIBUTION A L ETUDE DES LASERS A SEMI CONDUCTEURS DE TRES FORTE PUISSANCE MONOMODES TRANSVERSES A CAVITE INSTABLE EMETTANT A 1 48 M written by SYLVIE.. DELEPINE and published by . This book was released on 2000 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: CE MEMOIRE PORTE SUR LA CONCEPTION ET LA CARACTERISATION DE LASERS DE POMPE DE TRES FORTE PUISSANCE A SEMI-CONDUCTEURS EN VUE D'ATTEINDRE DES PUISSANCES COUPLEES DANS UNE FIBRE MONOMODE DE L'ORDRE DU WATT OPTIQUE A 1,48 M. NOUS AVONS ETUDIE LES RESONATEURS EVASES, INTEGRATION MONOLITHIQUE D'UNE SECTION MONOMODE TRANSVERSE A RUBAN DROIT AVEC UNE ELECTRODE LATERALEMENT EVASEE. NOUS AVONS PRESENTE UN TRAVAIL DE DIMENSIONNEMENT DE TELLES CAVITES LASER. LES CALCULS THERMIQUES ET OPTIQUES ABOUTISSENT A LA DEFINITION D'UNE STRUCTURE DE REFERENCE, DONT LES PARTICULARITES DE FONCTIONNEMENT PAR RAPPORT AUX CAVITES CLASSIQUES SONT EXPERIMENTALEMENT MISES EN EVIDENCE. NOUS AVONS ENSUITE DEGAGE LES MESURES CARACTERISTIQUES DE LA QUALITE DU FAISCEAU, PRINCIPALE LIMITATION DE CES LASERS. NOUS AVONS MONTRE QUE L'APPARITION D'UN MODE TRANSVERSE D'ORDRE SUPERIEUR EST LIEE A L'INSUFFISANCE DU FILTRAGE REALISE PAR LA SECTION MONOMODE. NOUS AVONS PROPOSE L'IMPLANTATION IONIQUE DU MILIEU ACTIF POUR AUGMENTER LES PERTES OPTIQUES DANS LES ZONES ADEQUATES, APPROCHE ORIGINALE DONT L'EFFICACITE A ETE DEMONTREE THEORIQUEMENT ET EXPERIMENTALEMENT. PAR AILLEURS, POUR LIMITER LE MECANISME DE CREUSEMENT DE TROU SPATIAL, NOUS NOUS SOMMES INTERESSES AUX ELECTRODES DISTRIBUEES PUIS AU PRINCIPE DE FAIBLE CONFINEMENT DANS LE MILIEU ACTIF. EN COMBINANT CES DIFFERENTES APPROCHES, 1,3 W A 1,48 M EN LIMITE DE DIFFRACTION ET EN REGIME CONTINU SONT DEPASSES. NOUS AVONS FINALEMENT ETUDIE LE COUPLAGE DANS UNE FIBRE MONOMODE DES RESONATEURS EVASES, DONT LE FAISCEAU EST DISSYMETRIQUE ET ASTIGMATE. APRES DIMENSIONNEMENT ET OPTIMISATION EXPERIMENTALE DU SYSTEME A TROIS LENTILLES RETENU, LA PUISSANCE COUPLEE DEPASSE 0,7 W DANS UNE FIBRE MONOMODE A PARTIR D'UNE DIODE UNIQUE EMETTANT A 1,48 M, ET LE TAUX DE COUPLAGE EFFECTIF ATTEINT 70%. UNE ETUDE ORIGINALE BASEE SUR DES MESURES DE TOLERANCES DE POSITIONNEMENT NOUS A PERMIS D'ETABLIR LES LIMITATIONS LIEES AUX ABERRATIONS ET LES POSSIBILITES D'AMELIORATION.
Download or read book Contribution l tude des ph nom nes non lin aires dans les lasers semi conducteurs written by François Girardin and published by . This book was released on 1995 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: CE TRAVAIL PORTE PRINCIPALEMENT SUR UNE ETUDE EXPERIMENTALE DU COMPORTEMENT DES LASERS A SEMI-CONDUCTEURS. IL A ETE INITIALEMENT MOTIVE PAR LA VOLONTE D'OPTIMISER ET DE CARACTERISER UNE NOUVELLE STRUCTURE DE LASERS DE TYPE DFB, LES LASERS A COEFFICIENT DE COUPLAGE VARIABLE, DEVELOPPES DANS LE BUT D'OBTENIR DES LASERS MONOMODES EMETTANT DE FORTES PUISSANCES. LA CONNAISSANCE ET LA MAITRISE DES EFFETS PHYSIQUES IMPLIQUES DANS LE FONCTIONNEMENT DES LASERS A SEMI-CONDUCTEURS PASSE PAR UNE CARACTERISATION EXPERIMENTALE DES COMPOSANTS. CELLE-CI PEUT ETRE REALISEE SUR LES CARACTERISTIQUES EXTERNES OU PAR UNE OBSERVATION INTERNE, ET DONC PLUS DIRECTE, DES PARAMETRES DE FONCTIONNEMENT. EN PARTICULIER, LA MESURE DE LA DENSITE DE PORTEURS LOCALE NOUS A PERMIS DE QUANTIFIER LES NON-UNIFORMITES PRESENTES DANS LES LASERS DFB A SAUT DE PHASE. D'AUTRE PART, L'ETUDE DU SPECTRE DE L'EMISSION SPONTANEE DONNE DES INFORMATIONS SUR LES ORIGINES DE LA SUPPRESSION DE GAIN. NOUS AVONS PU METTRE EN EVIDENCE LA PRESENCE D'UN ECHAUFFEMENT DES PORTEURS IMPORTANT DANS DES STRUCTURES A PUITS QUANTIQUES CONTRAINTS PAR CETTE METHODE. PARALLELEMENT, LE DEVELOPPEMENT D'UN MODELE DE LASERS DFB A ETE POURSUIVI. CELUI-CI NOUS A PERMIS DE METTRE EN EVIDENCE L'INFLUENCE DU RESEAU A COEFFICIENT DE COUPLAGE VARIABLE SUR LA VARIATION DE L'INDICE EFFECTIF DU MODE OPTIQUE. LE FONCTIONNEMENT DU LASER EST FORTEMENT PERTURBE PAR CETTE VARIATION. LES DISTRIBUTIONS DE PORTEURS ET DE PUISSANCE OPTIQUE SONT EGALEMENT CALCULEES ET COMPAREES AUX MESURES.
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 Pandex Current Index to Scientific and Technical Literature written by and published by . This book was released on 1971 with total page 1334 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Canadian Journal of Physics written by and published by . This book was released on 1991 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Artificial Intelligence in Society written by OECD and published by OECD Publishing. This book was released on 2019-06-11 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: The artificial intelligence (AI) landscape has evolved significantly from 1950 when Alan Turing first posed the question of whether machines can think. Today, AI is transforming societies and economies. It promises to generate productivity gains, improve well-being and help address global challenges, such as climate change, resource scarcity and health crises.
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 Molecular Beam Epitaxy written by John Wilfred Orton and published by . This book was released on 2015 with total page 529 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is a history of Molecular Beam Epitaxy (MBE) as applied to the growth of semiconductor thin films (note that it does not cover the subject of metal thin films). It begins by examining the origins of MBE, first of all looking at the nature of molecular beams and considering their application to fundamental physics, to the development of nuclear magnetic resonance and to the invention of the microwave MASER. It shows how molecular beams of silane (SiH4) were used to study the nucleation of silicon films on a silicon substrate and how such studies were extended to compound semiconductors such as GaAs. From such surface studies in ultra-high vacuum the technique developed into a method of growing high quality single crystal films of a wide range of semiconductors. Comparing this with earlier evaporation methods of deposition and with other epitaxial deposition methods such as liquid phase and vapour phase epitaxy (LPE and VPE). The text describes the development of MBE machines from the early 'home-made' variety to that of commercial equipment and show how MBE was gradually refined to produce high quality films with atomic dimensions. This was much aided by the use of various in-situ surface analysis techniques, such as reflection high energy electron diffraction (RHEED) and mass spectrometry, a feature unique to MBE. It looks at various modified versions of the basic MBE process, then proceed to describe their application to the growth of so-called 'low-dimensional structures' (LDS) based on ultra-thin heterostructure films with thickness of order a few molecular monolayers. Further chapters cover the growth of a wide range of different compounds and describe their application to fundamental physics and to the fabrication of electronic and opto-electronic devices. The authors study the historical development of all these aspects and emphasise both the (often unexpected) manner of their discovery and development and the unique features which MBE brings to the growth of extremely complex structures with monolayer accuracy.
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 AGARD Conference Proceedings written by North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polarimetric Synthetic Aperture Radar written by Irena Hajnsek and published by Springer Nature. This book was released on 2021-03-24 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book focuses on the practical application of electromagnetic polarimetry principles in Earth remote sensing with an educational purpose. In the last decade, the operations from fully polarimetric synthetic aperture radar such as the Japanese ALOS/PalSAR, the Canadian Radarsat-2 and the German TerraSAR-X and their easy data access for scientific use have developed further the research and data applications at L,C and X band. As a consequence, the wider distribution of polarimetric data sets across the remote sensing community boosted activity and development in polarimetric SAR applications, also in view of future missions. Numerous experiments with real data from spaceborne platforms are shown, with the aim of giving an up-to-date and complete treatment of the unique benefits of fully polarimetric synthetic aperture radar data in five different domains: forest, agriculture, cryosphere, urban and oceans.
Download or read book Government at a Glance Southeast Asia 2019 written by OECD and published by OECD Publishing. This book was released on 2019-09-10 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: Government at a Glance Southeast Asia 2019 is the first edition in the Government at a Glance series for the region. It provides the latest available data on public administrations in the 10 ASEAN member countries: Brunei Darussalam, Cambodia, Indonesia, Lao People’s Democratic Republic, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Viet Nam.
Download or read book Science Past Science Future written by Isaac Asimov and published by Doubleday Books. This book was released on 1975 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: A collection of 43 essays on many subjects, from the various sciences to essays about society.
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 Optical Properties Of Graphene written by Rolf Binder and published by World Scientific. This book was released on 2016-11-11 with total page 517 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive state-of-the-art overview of the optical properties of graphene. During the past decade, graphene, the most ideal and thinnest of all two-dimensional materials, has become one of the most widely studied materials. Its unique properties hold great promise to revolutionize many electronic, optical and opto-electronic devices. The book contains an introductory tutorial and 13 chapters written by experts in areas ranging from fundamental quantum mechanical properties to opto-electronic device applications of graphene.
