Dissertations / Theses on the topic 'Élargissement inhomogène des raies spectrales'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 31 dissertations / theses for your research on the topic 'Élargissement inhomogène des raies spectrales.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Eremeev, Kirill. "Brοadband emitting materials dοped with thulium and hοlmium iοns fοr sοlid-state lasers at 2 μm and beyοnd." Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMC232.
Full textNovel laser-active inorganic materials doped with thulium and holmium ions have been investigated for their potential in broadly tunable and ultrafast lasers operating in the short-wave infrared spectral range of 2 to 3 μm. Lasers emitting within this spectral range find numerous applications, including light detection and ranging systems, gas sensing, medicine. They are used as amplifying systems for high harmonic generation and terahertz generation, and further frequency conversion into the mid-infrared region.The present PhD thesis establishes relationships between the structural properties of oxide and fluoride crystalline materials, in the form of single crystals and transparent ceramics, and the spectroscopic properties of thulium and holmium dopant ions, along with their laser characteristics, which are essential for laser development. Moreover, the physical processes underlying unexpected laser behaviour are revealed. This systematic study of laser materials allows for the identification of the most promising compositions for the development of broadly tunable and ultrashort pulse lasers.This study mainly focuses on materials that exhibit significant inhomogeneous spectral line broadening, resulting in broad and structureless absorption and emission spectra of the dopant ions. In order to promote this effect, several strategies have been considered, including rare-earth ion clustering, local structure disorder, compositional disorder in solid-solution compounds, and phonon-sidebands arising from electron-phonon interactions.The formation of thulium and holmium clusters in calcium fluoride crystals enables efficient and broadly tunable laser operation around 2.1 μm. A polarized spectroscopic study of the emission properties of holmium ions in disordered calcium rare-earth aluminate crystals sheds light on its broadband spectral properties and on the role of multiphonon assisted emission, which occurs beyond electronic transitions, in unexpected laser emissions observed in mode-locked lasers. In solid-solution sesquioxide ceramics of the yttria-lutetia-scandia ternary system doped with thulium ions, there is a strong and nearly linear variation of the crystal-field strength with the mean size of the host-forming cation. This relationship allows for the customization of both the position and width of the emission band above 2 μm by appropriately adjusting the host composition. Highly efficient laser operations of thulium- and holmium-doped sesquioxides around 2.1 μm and 2.3 μm have been demonstrated
Labani, Boujemaâ. "Elargissement collisionnel des raies de vibration-rotation de molécules toupies asymétriques : Application à H2O." Besançon, 1986. http://www.theses.fr/1986BESA2008.
Full textTouati, Ahmed Kamel. "Analyse spectroscopique des plasmas en présence d'un champ magnétique : application au plasma de bord des tokamaks." Aix-Marseille 1, 2003. http://www.theses.fr/2003AIX11004.
Full textBerger, Jean-Philippe. "Etude des mécanismes de relaxation rovibrationnelle pour les mélanges H2-gaz rares, H2-N2 et H2-H2O par spectroscopie Raman stimulé en vue du diagnostic de la température dans un moteur fusée." Dijon, 1994. http://www.theses.fr/1994DIJOS028.
Full textFerri, Sandrine. "Modélisation non collisionnelle des effets d'élargissement électronique des raies de l'hydrogène dans les plasmas." Aix-Marseille 1, 1999. http://www.theses.fr/1999AIX11021.
Full textKaghat, Fahd. "Profils des transitions millimétriques : analyse par spectroscopie résolue en temps du rétrécissement et de l'asymétrie liés à la distribution des vitesses moléculaires." Lille 1, 1995. http://www.theses.fr/1995LIL10107.
Full textMasson, Olivier. "Etude des défauts de structure par diffraction des rayons X sur poudres : Utilisation d'un montage en réflexion asymétrique équipé d'un détecteur courbe à localisation." Limoges, 1998. http://www.theses.fr/1998LIMO0008.
Full textPriem, dominique. "Applications de la spectroscopique millimétrique : analyse de la forme des raies d'absorption de molécules atmosphériques (ozone, vapeur d'eau...) : détermination de la structure géométrique du chloroforme et du cyanosilane." Lille 1, 1998. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1998/50376-1998-163.pdf.
Full textSales, Nathalie. "Observation de l'émission à grande échelle des nuages d'Orion dans la raie à 3. 3 mum avec l'instrument Arome." Toulouse 3, 1992. http://www.theses.fr/1992TOU30068.
Full textTourrenc, Jean-Philippe. "Caractérisation et modélisation du bruit d'amplitude optique, du bruit de fréquence et de la largeur de raie de VCSELs monomodes émettant autour de 850 nm." Montpellier 2, 2005. http://www.theses.fr/2005MON20210.
Full textChadid, Merieme. "Ondes de choc, turbulence et modulations cycliques dans l'atmosphère de l'étoile variable pulsante RR Lyrae : une approche observationnelle." Toulouse 3, 1996. http://www.theses.fr/1996TOU30289.
Full textStehlé, Chantal. "Profils des raies de l'hydrogène dans les plasmas de basses densités." Paris 11, 1987. http://www.theses.fr/1987PA112124.
Full textKOUBITI, Mohammed. "Profils de raies dans les plasmas peu ou moyennement couplés : fondement et validation du modèle de fluctuation de fréquence." Aix-Marseille 1, 1997. http://www.theses.fr/1997AIX11025.
Full textTroitsyna, Larisa. "Approche semi-classique aux paramètres collisionnels de raies spectrales de CH3I pour applications atmosphériques et planétologiques." Electronic Thesis or Diss., Bourgogne Franche-Comté, 2021. http://www.theses.fr/2021UBFCD061.
Full textMethyl iodide molecule CH3I has come recently into focus of intense spectroscopic studies due to its role in the ozone layer depletion and its danger for human health in case of an accidental release in the atmosphere. For its atmospheric detection particularly suitable is the nu6 fundamental, which falls into the transparency window at 11 mu m. However, currently available spectroscopic line-shape parameters for CH3I perturbed by main atmospheric species are limited to some extremely scarce measurements at ambient temperature and are missing in spectroscopic databases. To supplement/replace the missing experimental data, in the frame of the French-Russian International Research Project SAMIA, room-temperature (296 K) line-broadening coefficients for the key atmospheric pairs CH3I-CH3I, CH3I-N2, CH3I-O2,CH3I-air are calculated semi-classically, with the use of the Robert-Bonamy formalism improved by exact trajectories, in wide ranges of rotational quantum numbers typically requested by databases (0 < J < 70, K < 20) and for all six sub-branches RP, PP, RQ PQ, RR, PR of the nu6 band; their vibrational dependence as well as sub-branch dependence and temperature dependence (with the traditional power and recently suggested double-power laws) are also addressed. Arguments are given to support this choice of the easily practicable method contrary to its advanced but less agreeing with measurements modifications. Comparisons are made with available measurements and alternative semi-empirical results, indicating the importance of the interaction potential model, in particular of its isotropic part governing the trajectories, for a realistic description of collisional line-widths
Bakri, Bilal. "Spectroscopie de rotation appliquée à l'étude de la relaxation collisionnelle de molécules d'intérêt atmosphérique, et à l'analyse de spectres millimétriques de NF3." Lille 1, 2004. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2004/50376-2004-135.pdf.
Full textLes coefficients d'élargissement collisionnel γ et. De dépendance en température sont déterminés pour l'ensemble des molécules étudiées, à partir d'observations faites à des températures comprises entre 240 K et 350 K Ces coefficients γ sont globalement déterminés avec une précision meilleure que 3%, 5% en ce qui concerne HN03. La dépendance en K des coefficients d'élargissement de deux rnolécuks symétriques perturbées par N2 à 300 K: CH3Cl et CH3CN, a été analysée, pour la première fois, pour des valeurs élevées de K L'ensemble des résultats expérimentaux sont. Favorablement comparés aux valeurs théoriques issues des formalismes de Birnbaum et de Robert et Bonamy et à celles obtenues dans d'autres laboratoires, à partir de techniques d'investigations différentes. La deuxième partie du travail concerne l'analyse des spectres de rotation de six états excités du trifluorure d'azote NF3 (. Toupie~symétrique de type C3V très peu étudiée dans le domaine rotationnel ). Cette étude a permis, entre autre, de déterminer précisément les paramètres spectroscopiques de l'ensemble des états excités étudiés et de définir complètement la structure à l'équilibre de cette molécule
Marque, Sylvain. "Production et études par RPE de radicaux phosphoranyle persilyles : applications en polarisation dynamique nucléaire." Aix-Marseille 3, 1996. http://www.theses.fr/1996AIX30103.
Full textMalnoult, Philippe. "Étude théorique et expérimentale des effets de hautes densités dans les spectres X émis par les plasmas de laser." Paris 11, 1989. http://www.theses.fr/1989PA112084.
Full textAtomic physics plays a fundamental part in equilibrium relations and in diagnostic methods for high density plasmas created by intense lasers. In order to extend the spectral perturbation theory to very high density plasmas we have explored the structure of transient molecules which arise from the ion position fluctuations in dense and relatively hot plasmas. A first calculation performed with the uniform electron gas (UEG) assumption, allows to obtain the interaction potential in a closed form and various atomic parameters which clearly show a drastic reduction of Stark efffect and also a possibility for exciting new spectral components. These UEG results have been used as initial conditions in a more general self-consistent field calculation which couples the Poisson equation for plasmas to the Schrödinger equation for electronic bound states of transient molecules. Spectroscopic measurements have been made on plasmas obtained by focusing a Neodyme laser beam with quadruple frequency (0. 263 μm) on LiF targets. To discriminate the radiative transfer and transverse inhomogeneity effects from the particles perturbation effects, the target thickness has been calibrated between 40 and 120 μm. By comparing the experimental line shapes with the theoretical ones, we have been able to draw the density profile which goes from 10^22 cm-3 to 10^23 cm-3 over 15 μm along the laser axis. A special study of the dense region has shown that on the red wing of F IX Lyman β appears a satellite, in good agreement with the above-mentioned transient molecule theory
Benec'h, Sébastien. "Modélisation des coefficients d'élargissement collisionnel des molécules du type toupie-symétrique impliquées dans la physico-chimie de l'atmosphère." Angers, 2002. http://www.theses.fr/2002ANGE0054.
Full textMichaut, Xavier. "Influence de la relaxation collisionnelle sur les raies Raman purement rotationnelles de H2 perturbé par H2, He, Ar, N2 et H2O en vue du diagnostic optique de la température : comparaison avec les raies rovibrationnelles de la branche Q." Dijon, 1999. http://www.theses.fr/1999DIJOS048.
Full textDufour, Emmanuelle. "Effets de corrélation de charges dans les plasmas denses et chauds." Aix-Marseille 1, 2003. http://www.theses.fr/2003AIX11049.
Full textLhuissier, Jean-François. "Etude de raies d'argon ionisé élargies par effet Stark." Rouen, 1987. http://www.theses.fr/1987ROUES002.
Full textBoland, Denis. "Contributions au formalisme de l'élargissement Stark des profils de raies." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4722/document.
Full textSpectroscopy is an essential tool for plasma diagnostics, especially for studying stars, allowing hope to understand always better their origin and their evolution, or for laboratory plasmas, especially those encountered in the experiments for controlled thermonuclear fusion, such as ITER.Modeling profiles of Lyman-alpha hydrogen leads to develop different approaches whose formalism deserves to still remain under investigation, and can possibly be enriched, to improve our diagnostic capabilities. We therefore explored the subject successively by a path integral approach, in order to retain maximum information related to the quantum nature of the interaction process, then the role of chronology, as the interaction potential of the atomic system with the plasma does not commute at two different times, and finally we worked on an approach modeling the electric field by stochastic processes whose statistical properties determine the characteristics of the line profiles of the studied plasmas. In the latter case, the work shows that the modeling of the electric field by stochastic processes contains serious research possibilities which should be able to further improve present results
Hamady, Mohamad. "Calcul du transfert radiatif dans une lampe à décharge à forte intensité par une technique de lancer de rayons." Toulouse 3, 2009. http://www.theses.fr/2009TOU30142.
Full textThis work presents a method for calculating radiative transfer in high intensity discharge lamps using a technique of ray tracing. The considered discharge is divided into elementary cells responsible for launching rays in all directions. We determine for each ray the crossed mesh and the distance travelled in each mesh. The radiative transfer equation (RTE) is then solved along each ray. We calculate thus the net emission coefficient, the spectral flux emitted by the discharge and also the photometric curves. These calculations consider that the discharge has a cylindrical symmetry and assume that the plasma is at local thermodynamic equilibrium (LTE). Hence, the only knowledge of the temperature profile and pressure is sufficient to calculate the chemical composition of plasma and to account the mechanisms of broadening of spectral lines in the treatment of radiative transfer. This calculation method is applied into lamps containing pure mercury and mercury doped with metal halides (thallium iodide). We deduce from energy calculations the photometric characteristics: Luminous flux, luminous efficacy, photometric curves, color temperature and chromaticity coordinates. We show the influence of thallium lines in photometric characteristics of the lamp
Lapointe, Marc-André. "Lasers à fibre de puissance opérés en régime continu." Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27088/27088.pdf.
Full textThis research project focuses on high power fiber lasers operated in the continuous regime. The main objective is the implementation of a 400-W fiber laser using ytterbium- doped double clad fiber. The wide variety of high power fiber lasers assembled during this work has enabled the study of the thermal effects, the power limitations and the behavior of the output spectrum. The study includes simulations that characterize the behavior of fiber lasers operated in the continuous regime. Different laser configurations were tested at a signal power of 100 W. The heat transfer in double clad fibers was analyzed to circumvent the difficulties caused by the important amount of heat generated by these lasers. The concept of contact resistance is brought in to explain the temperature rise of active fibers. This was necessary for the realization of single-mode fiber lasers with over 350W of output power. The output power was only limited by the availability of pumps. Several compromises were necessary to achieve the high output power and the diffraction-limited beam quality. Thus, the photodarkening of the ytterbium doped fiber is still an issue for this kind of lasers. A tool to predict the spectral broadening of high power fiber lasers has been developed. It is shown that four-wave mixing broadens the outpu t spectrum of these lasers as a function of output power. The broadening of the output spectrum has been experimentally verified by the implementation of various lasers with different configurations. A theoretical model is presented, which shows a good agreement with experimental data.
Marandet, Yannick. "Couplages entre les phénomènes radiatifs et de transport dans les plasmas hors d'équilibre." Aix-Marseille 1, 2003. http://www.theses.fr/2003AIX11048.
Full textAttafi, Yosra. "Étude des effets des collisions dans les spectres infrarouges de CH₃I, molécule d’intérêt atmosphérique." Electronic Thesis or Diss., Université Paris Cité, 2020. http://www.theses.fr/2020UNIP7086.
Full textThe work presented in this manuscript is devoted to the study of the effects of collisions in the infrared spectra of CH₃I, which is an important source of iodine, which is a catalyst for ozone destruction. Good modelling of its absorption spectrum is therefore essential for atmospheric concentration measurements. In international databases, the band ν6 is not mentioned due to the lack of spectroscopic parameters. Being very intense and localized in the atmospheric window of 11 μm, the ν6 band could be used for future IR detection of CH₃I, by instruments probing in the IR, such as the IASI-NG instrument under preparation. But first, it is necessary to provide the spectroscopic parameters of CH₃I, using laboratory spectroscopy. It is in this context that our work has been carried out. The manuscript consists of five parts. The first part concerns the spectroscopic properties of the CH3I molecule. The second part is dedicated to the apparatus, with a description of the Bruker IFS125HR FTIR spectrometer. In the third part, we present the results of the line intensities and self-broadening coefficients that are extracted from the recorded spectra. The fourth part presents the results obtained on N₂, O₂ broadening and shift coefficients. The last part is devoted to the interpretation of the collisional widening measurements, previously obtained using theoretical calculations. The dependence of these parameters on the quantum numbers J and K has been studied
Aballéa, Ludovic. "Développement d'un spectromètre térahertz par différence de fréquences : application à des molécules d'intérêt atmosphérique." Electronic Thesis or Diss., Lille 1, 2009. http://www.theses.fr/2009LIL10020.
Full textThis thesis reports on the construction of a new experimental set up for Terahertz spectroscopy based on the generation of the frequency difference of two near infrared laser diodes at 820nm on a GaAs substrate device. The first chapter describes the renewal of the interest for T-rays. The second chapter treats the FIR generation by frequency difference on the GaAs semiconductor device and its uses for spectroscopy. The broad tunability of this Far Infrared radiation obtained by double-pass acousto-optic modulators setup is also seen. The third chapter discusses about stabilisation of infrared sources by the Pound-Drever-Hall method using a high finesse cavity to generate a high spectral purity of the FIR emission. Finally, the spectrometer is characterised by measurements of the rotationnal spectrum of methyl-chloride and used in a primary study of the broadening parameter of water lines by N2, O2 and air
Maaroufi, Nourhene. "Détermination des paramètres spectroscopiques des bandes v1 et v3 de NH3 par spectroscopie infrarouge." Electronic Thesis or Diss., Sorbonne Paris Cité, 2019. http://www.theses.fr/2019USPCC099.
Full textThe aim of this work was to determine the parameters of the absorption lines of the ammonia molecule for atmospheric applications. In this regard, we measured, at room temperature, the intensities, the broadening and the shift coefficients of the lines of the bands v1, v3, 2v4, and 4v2 in the spectral region 3050-3600 cm-1 of self-disturbed NH3. These measurements were carried out in a large number of branches of these bands with very high precision using a high resolution Fourier transform infrared spectrometer (0.008 cm-1).These spectroscopic parameters were determined using a multi-pressure fitting technique using two different profiles: a Voigt profile and a Rosenkranz profile.The manuscript consists of five parts. The first part concerns the spectroscopic properties of ammonia. The second part is dedicated to the apparatus, with the description of the Bruker IFS125HR IRTF spectrometer. In the third part, we expose the results of the line intensities and self-broadenings of isolated lines, which are extracted from the recorded spectra, bands v1, v3, 2v4 and 4v2 of NH3. The fourth part presents the results obtained on line shifts and the interference effects between the components of the doublets of the v1 and v3 bands of NH3.To interpret the results of the line width measurements of the self-disturbed NH3 collisional system, we will present in chapter 5 the formalism adopted for the calculation of these widths. A comparison between the calculated and measured widths makes it possible to test the validity of the formalism used
Ribière, Maxime. "Spectroscopies d'émission et d'absorption appliquées à l'analyse de plasmas produits par impulsion laser." Phd thesis, Rouen, 2008. http://www.theses.fr/2008ROUES059.
Full textThis work has been performed in the purpose of probing solid surfaces by using LIPS (laser induced plasma) technique. The behavior of the produced plasma is very difficult to simulate owing to the shortness of the involved time and space scale. Besides classical emission spectroscopy diagnostics, we have put into operation an original absorption experiment which provides more reliable and numerous informations about the plasma temperature and number densities. This study, which couples experiment and theory through the resolution of the radiative transfer equation, is based on the comparison between the experimental and the simulated profiles of the 308. 21 and 396. 15 nm Al(I) resonant lines. Special attention has been turned to the ion and electron Stark broadening and self-absorption effects. An important departure from equilibrium is put into evidence throughout the plasma recombination. The measurement of the aluminum fundamental state which is of prime importance in the validation of any collisional-radiative model dedicated to this complex situation has been carried out in a large pressure range (5 to 105 Pa). The measurement of the relaxation times highlights the major role played by the diffusion in the relaxation of the plasma species
Ribière, Maxime. "Spectroscopies d'émission et d'absorption appliquées à l'analyse de plasmas produits par impulsion laser." Phd thesis, Université de Rouen, 2008. http://tel.archives-ouvertes.fr/tel-00443037.
Full textAballéa, Ludovic. "Développement d'un spectromètre térahertz par différence de fréquences : application à des molécules d'intérêt atmosphérique." Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10020/document.
Full textThis thesis reports on the construction of a new experimental set up for Terahertz spectroscopy based on the generation of the frequency difference of two near infrared laser diodes at 820nm on a GaAs substrate device. The first chapter describes the renewal of the interest for T-rays. The second chapter treats the FIR generation by frequency difference on the GaAs semiconductor device and its uses for spectroscopy. The broad tunability of this Far Infrared radiation obtained by double-pass acousto-optic modulators setup is also seen. The third chapter discusses about stabilisation of infrared sources by the Pound-Drever-Hall method using a high finesse cavity to generate a high spectral purity of the FIR emission. Finally, the spectrometer is characterised by measurements of the rotationnal spectrum of methyl-chloride and used in a primary study of the broadening parameter of water lines by N2, O2 and air