Download or read book SPECTROSCOPIE LASER A DEUX PHOTONS D IONS DE TERRES RARES EN MILIEU CRISTALLIN written by and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: CE TRAVAIL EST CONSACRE A L'ETUDE DU PROCESSUS D'ABSORPTION A DEUX PHOTONS DANS DES IONS DE TERRES RARES INCORPORES DANS DES MATRICES CRISTALLINES. DE NOUVELLES TRANSITIONS A DEUX PHOTONS ONT ETE OBSERVEES ET ANALYSEES THEORIQUEMENT POUR LES IONS EU3+ ET GD3+. DE PLUS, LA VARIATION DES INTENSITES DE TRANSITIONS EN FONCTION DE LA POLARISATION A ETE REPRODUITE DE MANIERE SATISFAISANTE DANS LE CADRE D'UNE ANALYSE THEORIQUE COMPORTANT LES TERMES DU SECOND ORDRE ET DU TROISIEME ORDRE DE L'AMPLITUDE DE PROBABILITE D'UNE TRANSITION A N PHOTONS.

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 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 NONLINEAIRE DES CRISTAUX DOPES PAR DES IONS DE TERRES RARES written by Wolfgang Beck and published by . This book was released on 1998 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: CETTE THESE EST CONSACREE A L'ETUDE EXPERIMENTALE ET THEORIQUE DE LA PHOTOIONISATION ET DU PIEGAGE D'ELECTRONS, AINSI QU'AUX MECANISMES D'ELARGISSEMENT DES RAIES ELECTRONIQUES DANS DES CRISTAUX DOPES AU SAMARIUM. LES METHODES SPECTROSCOPIQUES DE L'ABSORPTION LINEAIRE, DE FLUORESCENCE, DE DRASC ET D'EXCITATION DRASC ONT PERMIS D'IDENTIFIER LES PIEGES D'ELECTRONS DANS DES ECHANTILLONS DE CAF#2 : SM, TRAITES ET NON-TRAITES AUX RAYONS . DANS LE PREMIER CAS, IL S'AGIT DE PAIRES DE TROUS AUTO-PIEGES, DANS LE DEUXIEME, D'AGREGATS DE SM#3#+. EN CE QUI CONCERNE LES LARGEURS HOMOGENES DES RAIES DE SM#2#+ DANS CAF#2, LES RESULTATS EXPERIMENTAUX SONT INTERPRETES PAR UNE THEORIE PRENANT EN COMPTE LE COUPLAGE ELECTROPHONON. AVEC LA TECHNIQUE DRASC POLARISEE, ON EXAMINE POUR LA PREMIERE FOIS LE DEPHASAGE D'UNE RAIE RAMAN D'UN ION DE TERRE DANS UN CRISTAL. PAR LA TECHNIQUE DU CREUSEMENT DE TROU SPECTRAL PERMANENT ON ETUDIE EGALEMENT LE DEPHASAGE D'UNE RAIE DANS LE VISIBLE. LA MESURE SIMULTANEE DE LA DEPENDANCE EN TEMPERATURE DES LARGEURS ET DES POSITIONS SPECTRALES DES DEUX TRANSITIONS, AVEC LA THEORIE PRESENTEE DANS CETTE ETUDE, PERMET DANS LES DEUX CAS L'IDENTIFICATION DES PROCESSUS DE DEPHASAGE. LA DERNIERE PARTIE DE CETTE THESE TRAITE DU CREUSEMENT DE TROUS PERMANENTS, AUX TEMPERATURES ELEVEES, DANS LE CRISTAL MIXTE CA#1#-#XY#XF#2#+#X : SM. ON OBSERVE DES TROUS PERMANENTS DE 8 A 200 K.

Download or read book SPECTROSCOPIE DYNAMIQUE DE FLUORESCENCE ET POTENTIALITE LASER DES CRISTAUX Y 2SIO 5 written by CHUIN.. LI and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: LES EMISSIONS LASER A 1.55 ET 2 MICRON DES IONS DE TERRE-RARES ER#3#+, TM#3#+ ET HO#3#+ SONT SUSCEPTIBLES DE NOMBREUSES APPLICATIONS TANT DANS LE DOMAINE DES TELECOMMUNICATIONS PAR FIBRES OPTIQUES QUE DANS LES DOMAINES MEDICAL ET MILITAIRE. CETTE THESE PORTE PRECISEMENT SUR L'ETUDE SPECTROSCOPIQUE ET DYNAMIQUE ET SUR L'EVALUATION DES POTENTIALITES LASER DE MONOCRISTAUX D'ORTHOSILICATE D'YTTRIUM DE FORMULE CHIMIQUE Y#2SIO#5 DOPES SOIT PAR LES IONS ER#3#+ OU TM#3#+ SOIT CODOPES PAR LES IONS YB#3#+ ET ER#3#+, L'ION YB#3#+ SERVANT D'ADSORBANT (SENSIBILISATEUR) POUR LA LUMIERE D'EXCITATION. UNE PART IMPORTANTE DU TRAVAIL EST CONSACREE A LA DESCRIPTION ET A L'UTILISATION DE LA THEORIE DE JUDD-OFELT DANS LA DETERMINATION DES DIFFERENTS PARAMETRES REGISSANT LES PROPRIETES OPTIQUES DE CES CRISTAUX. LES RESULTATS MONTRENT QUE LES CRISTAUX DOPES ER#3#+, GRACE A UNE EMISSION INFRAROUGE BIEN CENTREE AUTOUR DE 1.55 MICRON, UNE BONNE SECTION EFFICACE D'EMISSION STIMULEE, DES RELAXATIONS NON-RADIATIVES ENTRE ETATS EXCITES FAVORABLES A UN BON PEUPLEMENT DE L'ETAT EMETTEUR, PEUVENT CONCURRENCER VALABLEMENT LES VERRES PHOSPHATES DOPES ER#3#+ KIGRE QE-7 DU COMMERCE, TOUT EN PRESENTANT DE MEILLEURES PROPRIETES THERMOMECANIQUES. LES CRISTAUX DOPES TM, AVEC UNE EMISSION LARGE BANDE AUTOUR DE 2 MICRON ET LES SECTIONS EFFICACES STIMULEES NOTABLEMENT PLUS ELEVEES QUE DANS LA PLUPART DES AUTRES SYSTEMES, APPARAISSENT QUANT A EUX COMME DE BONS CANDIDATS POUR UNE EMISSION LASER ACCORDABLE ENTRE ENVIRON 1.8 ET 2.1 MICRON

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 1320 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Applied Mineralogy in the Mining Industry written by W. Petruk and published by Elsevier. This book was released on 2000-11-29 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: Techniques of performing applied mineralogy investigations, and applications and capabilities of recently developed instruments for measuring mineral properties are explored in this book intended for practicing applied mineralogists, students in mineralogy and metallurgy, and mineral processing engineers. The benefits of applied mineralogy are presented by using in-depth applied mineralogy studies on base metal ores, gold ores, porphyry copper ores, iron ores and industrial minerals as examples. The chapter on base metal ores includes a discussion on the effects of liberation, particle sizes and surfaces coatings of Pb, Cu, Fe, Ca and So4- on the recoveries of sphalerite, galena and chalcopyrite. The chapter on gold discusses various methods of determining the quantities of gold in different minerals, including 'invisible' gold in pyrite and arsenopyrite, so that a balance of the distribution of gold among the minerals can be calculated. This book also discusses the roles of pyrite, oxygen, moisture and bacterial (thiobacillus ferrooxidans) on reactions that produce acidic drainage from tailings piles, and summarizes currently used and proposed methods of remediation of acidic drainage.

Download or read book Flexoelectricity in Liquid Crystals written by Agnes Buka and published by World Scientific. This book was released on 2013 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book intends to give a state-of-the-art overview of flexoelectricity, a linear physical coupling between mechanical (orientational) deformations and electric polarization, which is specific to systems with orientational order, such as liquid crystals. Chapters written by experts in the field shed light on theoretical as well as experimental aspects of research carried out since the discovery of flexoelectricity. Besides a common macroscopic (continuum) description the microscopic theory of flexoelectricity is also addressed. Electro-optic effects due to or modified by flexoelectricity as well as various (direct and indirect) measurement methods are discussed. Special emphasis is given to the role of flexoelectricity in pattern-forming instabilities. While the main focus of the book lies in flexoelectricity in nematic liquid crystals, peculiarities of other mesophases (bent-core systems, cholesterics, and smectics) are also reviewed. Flexoelectricity has relevance to biological (living) systems and can also offer possibilities for technical applications. The basics of these two interdisciplinary fields are also summarized.

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 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.

Download or read book U S Research Reactors written by Battelle Memorial Institute. Columbus Laboratories and published by . This book was released on 1957 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Physical Properties of Amorphous Materials written by David Adler and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Institute for Amorphous Studies was founded in 1982 as the international center for the investigation of amorphous mate rials. It has since played an important role in promoting the und er standing of disordered matter in general. An Institute lecture series on "Fundamentals of Amorphous Materials and Devices" was held during 1982-83 with distinguished speakers from universities and industry. These events were free and open to the public ,and were attended by many representatives of the scientific community. The lectures themselves were highly successful inasmuch as they provided not only formal instruction but also an opportunity for vigorous and stimulating debate. That last element could not be captured within the pages of a book I but the lectures concentrated on the latest advances in the field I which is why their essential contents are he re reproduced in collective form. Together they constitute an interdisciplinary status report of the field. The speakers brought many different viewpoints and a variety of back ground experiences io bear on the problems involved I but though language and conventions vary I the essential unity of the concerns is very clear I as indeed are the ultimate benefits of the many-sided approach.

Download or read book Anticancer Molecules written by Hiroshi Maruta and published by . This book was released on 1999 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume discusses the value of research on tumor suppressor genes and the structure-function relationship of the corresponding proteins. The applicability of these non-peptide molecules to anti-cancer drugs is also taken up; and by focusing on contemporary research issues in the field, the book aims to promote understanding and cooperation between industrial and academic researchers.

Download or read book Nonlinear Optical Materials written by Jerome V. Moloney and published by Springer Science & Business Media. This book was released on 1998-08-13 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mathematical methods play a significant role in the rapidly growing field of nonlinear optical materials. This volume discusses a number of successful or promising contributions. The overall theme of this volume is twofold: (1) the challenges faced in computing and optimizing nonlinear optical material properties; and (2) the exploitation of these properties in important areas of application. These include the design of optical amplifiers and lasers, as well as novel optical switches. Research topics in this volume include how to exploit the magnetooptic effect, how to work with the nonlinear optical response of materials, how to predict laser-induced breakdown in efficient optical devices, and how to handle electron cloud distortion in femtosecond processes.