Dissertationen zum Thema „Impulsions laser nanosecondes“
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Amiard, Hudebine Gabriel. „Développement de sources lasers nanosecondes, picosecondes et femtosecondes et applications“. Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0024/document.
This two-part thesis focuses on the development of nano and picosecond laser sources and their applications. The first part presents the study, and the realization of a nanosecond laser amplifier chain for the ignition of turboshaft engines. After the repport of the performances and the evolution of this amplifier chain will be presented the results of the tests carried out on a combustion chamber on a test bench at ONERA under low temperatures and low pressures conditions. The second part of this thesis deals with the development of an optical parametric oscillator (OPO) in order to tune in the infrared the wavelength of a pulsed picosecond or femtosecond laser at high cadency and high average power. After presenting the OPO cavity and its performance, we will detail the ability of this OPO to generate compressed femtosecond pulses from pump chirped pulses
Mhalla, Taghrid. „Micro-ablation athermique de matériaux transparents par absorption multiphotonique avec une micro-puce laser amplifiée Nd : YAG à impulsions vertes sub-nanosecondes“. Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAY059/document.
Microchip lasers with sub-nanosecond pulses are attractive alternative to femtosecond lasers for micromachining in transparent materials by multiphoton absorption. These lasers can easily reach pulse peak powers that are needed to trigger ablation in all materials, including diamond, ceramics, plastics, and glasses. In addition, they are low cost with compact and rugged design. In this thesis, a microchip laser (532 nm, 300 ps) has been used for micro-engraving and marking different types of transparent materials such as borosilicate D263, BK7, and SBS thermoplastic. Experimental resultsare rationalized by the model of matter explosion following the plasma generation induced by the laser two-photon absorption. Sub-micron resolution embedded marking is demonstrated inside borosilicate glass. Micro fluidic channels for optical sensors are engraved on BK-7 glass with ion-doped waveguides. Arrays of dense micro channels are fabricated at the surface of thermoplastics with a zone affected by thermal effects limited to the micron range. In summary, this thesis demonstrates that this type of laser can be efficiently used for high-resolution micro-machining transparent materials with minimal thermal effects
Lago, Laure. „Amplification fibrée de forte énergie pour les lasers de puissance“. Thesis, Lille 1, 2011. http://www.theses.fr/2011LIL10137/document.
This work concerns the development of a double-clad ytterbium-doped single-mode microstructured flexible fiber-based amplifier, in the nanosecond, multi-kiloHertz and milliJoule regime, for large-scale laser facilities seeding. We have used a multi-stage master oscillator power amplifier fibered architecture. A numerical model of ytterbium-doped double-clad fiber-based amplification, including amplified spontaneous emission, was developed in order to study the behaviour of such amplifier and to correctly design the experimental set-up. This model was completed by a feed-back algorithm to numerically predict the optimal temporal shape to compensate the gain saturation process. We demonstrated experimental results in good agreement with numerical simulations, with the following performances: 0.5 mJ pulse energy, at a frequency repetition from 1 kHz to 10 kHz, with a narrow bandwidth spectrum centred at 1053 nm wavelength, with 10 ns pulse duration on a perfect super-Gaussian temporal profile, an optical signal-to-noise ratio better than 50 dB and a polarization extinction ratio of 20 dB. We checked that the beam quality was diffraction limited, with an M² measurement of 1.1. Moreover, the system can deliver energies up to 1.5 mJ. Then, we took the advantage of such results to amplify chirped pulses. We demonstrated 0.7 mJ pulse energy, with 570 fs duration at 10 kHz repetition frequency
Lago, Laure. „Amplification fibrée de forte énergie pour les lasers de puissance“. Electronic Thesis or Diss., Lille 1, 2011. http://www.theses.fr/2011LIL10137.
This work concerns the development of a double-clad ytterbium-doped single-mode microstructured flexible fiber-based amplifier, in the nanosecond, multi-kiloHertz and milliJoule regime, for large-scale laser facilities seeding. We have used a multi-stage master oscillator power amplifier fibered architecture. A numerical model of ytterbium-doped double-clad fiber-based amplification, including amplified spontaneous emission, was developed in order to study the behaviour of such amplifier and to correctly design the experimental set-up. This model was completed by a feed-back algorithm to numerically predict the optimal temporal shape to compensate the gain saturation process. We demonstrated experimental results in good agreement with numerical simulations, with the following performances: 0.5 mJ pulse energy, at a frequency repetition from 1 kHz to 10 kHz, with a narrow bandwidth spectrum centred at 1053 nm wavelength, with 10 ns pulse duration on a perfect super-Gaussian temporal profile, an optical signal-to-noise ratio better than 50 dB and a polarization extinction ratio of 20 dB. We checked that the beam quality was diffraction limited, with an M² measurement of 1.1. Moreover, the system can deliver energies up to 1.5 mJ. Then, we took the advantage of such results to amplify chirped pulses. We demonstrated 0.7 mJ pulse energy, with 570 fs duration at 10 kHz repetition frequency
El, bassri Farid. „Sources lasers déclenchées nanosecondes : Applications à la spectroscopie Raman cohérente sous champ électrique“. Thesis, Limoges, 2014. http://www.theses.fr/2014LIMO0060/document.
Thanks to their compactness, robustness and low cost, pulsed nanosecond microlasers are particularly attractive sources for different detection and analysis systems, particularly flow cytometers or devices for CARS (Coherent Anti Raman Stokes Scattering) spectroscopy. However, these applications require reduced time jitter and increased repetition rate. The first part of this thesis proposes novel solutions to achieve the required performance from passively Q-switched microlasers, which are based on an hybrid coupled-cavity and intensitymodulated pump wave. A repetition rate greater than 30 kHz with jitter remaining lower than 200 ns is reached. Pulsed fiber microlasers operating by gain switching are also studied, showing that pulses with low timing jitter, at a repetition rate of more than 2 MHz can be obtained. The last part is devoted to the development and the implementation of a new system of CARS spectroscopy assisted by a high-voltage electrical stimulation. This device, based on an amplified microlaser, allows to substract the non-resonant background noise in the measurements. Thus, a fine spectroscopic analysis of the response of different environments of interest in continuous or pulsed field can be achieved. It may lead to a new method for field microdosimetry. Various applications, including granulometry at the micro or nanometric scale and the identification of markers for biology, are shown
Scol, Florent. „Amplification et transport fibré d’impulsions énergétiques pour les pilotes des installations laser de puissance“. Thesis, Lille 1, 2017. http://www.theses.fr/2017LIL10129/document.
Compactness, stability and beam quality are some benefits of fiber lasers. In large scale laser facilities, those systems are already used to generate and amplify pulses but are limited to the nanojoule range. The goal of this thesis consists in building a millijoule range system satisfying large scale laser facility requirements. Amplification and beam delivery systems have been considered. In the first case, an all-fiber MOPA has been realized. Using a 32 µm mode field diameter tapered fiber, we amplified 10 ns pulses up to 500 µJ with excellent temporal, spectral and spatial properties. In a second step, we consider the fiber beam delivery of those pulses over 15 m. In order to minimize nonlinear effects, hollow-core fibers have been used. This way, thanks to a 21 µm mode field diameter fiber, 30 kW peak power nanosecond pulses have been delivered over 15 m with negligible temporal and spectral distortions. In addition of amplification and beam delivery, we also considered technological building blocks which could be used to modified actual fiber seeder architecture. Chirped laser diode has been used to generate pulses and allowed us to finally obtained 1,25 mJ with our MOPA system. Fiber spatial beam shaping has also been performed in the 100 µJ range thanks to a microstructured, single-mode, polarization maintaining fiber which delivers a coherent top-hat beam. Finally, this work confirms the great potential of fiber systems for high energy amplification and beam delivery for the next generation of large scale laser facilities seeder
Scol, Florent. „Amplification et transport fibré d’impulsions énergétiques pour les pilotes des installations laser de puissance“. Electronic Thesis or Diss., Lille 1, 2017. http://www.theses.fr/2017LIL10129.
Compactness, stability and beam quality are some benefits of fiber lasers. In large scale laser facilities, those systems are already used to generate and amplify pulses but are limited to the nanojoule range. The goal of this thesis consists in building a millijoule range system satisfying large scale laser facility requirements. Amplification and beam delivery systems have been considered. In the first case, an all-fiber MOPA has been realized. Using a 32 µm mode field diameter tapered fiber, we amplified 10 ns pulses up to 500 µJ with excellent temporal, spectral and spatial properties. In a second step, we consider the fiber beam delivery of those pulses over 15 m. In order to minimize nonlinear effects, hollow-core fibers have been used. This way, thanks to a 21 µm mode field diameter fiber, 30 kW peak power nanosecond pulses have been delivered over 15 m with negligible temporal and spectral distortions. In addition of amplification and beam delivery, we also considered technological building blocks which could be used to modified actual fiber seeder architecture. Chirped laser diode has been used to generate pulses and allowed us to finally obtained 1,25 mJ with our MOPA system. Fiber spatial beam shaping has also been performed in the 100 µJ range thanks to a microstructured, single-mode, polarization maintaining fiber which delivers a coherent top-hat beam. Finally, this work confirms the great potential of fiber systems for high energy amplification and beam delivery for the next generation of large scale laser facilities seeder
Denis, Maxime. „Construction d'une expérience de Condensat de Bose-Einstein de 41K pour l'étude du rotateur frappé atomique“. Electronic Thesis or Diss., Université de Lille (2022-....), 2022. http://www.theses.fr/2022ULILR064.
This manuscript presents the realization of an experimental device to produce Bose-Einstein condensates of potassium 41. This experiment was built to study the model of the kicked rotor in the presence of interactions. The choice of potassium 41 for this experiment is motivated by two reasons. The first is that the diffusion length of this atom is positive (allowing easy condensation) and has accessible Feshbach resonances. The second is that the wavelengths of its cooling transitions can be generated by powerful fiber laser sources in the telecom domain doubled in frequency. This has the advantage of being able to manufacture stable and robust laser systems for laser cooling and optical trapping of potassium 41. The particularity of our system lies in the frequency generation that takes place before the high power amplification and frequency doubling stages. The development of these laser benches acting on the two cooling transitions D1 and D2 enabled the laser cooling stages to be completed. Thanks to these laser benches, a magneto-optical trap gathering 3x10^(9) atoms was obtained. Compression and cooling with grey molasses of this magneto-optical trap allowed to reach a temperature of 16 µK and a density in the space of phases of 10^(-6). The following evaporative cooling steps are carried out successively with a quadrupolar trap, a hybrid trap (quadrupolar trap + optical trap) and to finish a crossed optical dipole trap. Condensates of 500,000 atoms were observed in this crossed optical dipole trap. We also identified Feshbach resonances that will allow the control of interactions. For the study of the kicked rotor, an original pulsed laser system was designed in parallel. The realization of this system was made from a high-power amplified telecom pulsed laser doubled in frequency. This system produces near infrared pulses at a repetition frequency between 100 kHz to 500 kHz with peak optical power up to 350W. This pulsed laser bench allowed us to perform the first experiments of the kicked rotor from this experiment. A control of the interactions with the identified Feshbach resonances will allow us to study the model of the kicked rotor in the presence of interactions
Mauger, Sarah. „Couplage entre auto-focalisation et diffusion Brillouin stimulée pour une impulsion laser nanoseconde dans la silice“. Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00638962.
Juhel, Marc. „Traitement de surface par une impulsion laser de 15 nanosecondes : application à la formation d'alliages“. Grenoble 1, 1990. http://www.theses.fr/1990GRE10111.
Gagné, Philippe. „Génération de supercontinuum dans l'infrarouge en régime nanoseconde“. Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/27327/27327.pdf.
CHIBANE, F. „Reponse resistive des films supraconducteurs haute t#c a des impulsions laser nanoseconde. Determination du temps d'interaction electron-phonon“. Paris 7, 1991. http://www.theses.fr/1991PA077279.
Huynh, Thi Trang Dai. „Etude de la dynamique de formation de nanostructures périodiques sur une couche mince de cuivre induites par impulsions laser nanoseconde et picoseconde à 266 nm“. Thesis, Orléans, 2014. http://www.theses.fr/2014ORLE2044/document.
Periodic surface nanostructures induced by laser have attracted particular attention because of their applications in the domain of micro and nanotechnologies such as lithography, high density data storage, nano- and micro-electromechanical systems (NEMS/MEMS). The dynamic of their formation on the surface of copper thin film deposited on silicon and glass substrates was investigated in this present work. Two methods are used in this analysis: ex situ analyses by Scanning and Transmission Electron Microscopy (SEM/TEM), Atomic Force Microscopy (AFM) and in situ diagnostic by Time Resolved Reflectivity method (TRR). The process of phase change (melting, ablation, thin film removal …) and surface morphology modification at the nanoscale are studied with respect to irradiation dose (the fluence and the number of laser shots), the thickness of thin film and the substrate thermal conductivity in the pico- and nanosecond regime. Namely, nanostructures with a spatial period of 266 nm (close to the irradiation wavelength (λ)), 130 nm (λ/2) and 60 nm (λ/4) were successfully obtained. The global relationship between the laser parameters (i.e. fluence and number of laser shots) and nanostructure formation was established in the form of a 2D map. Lastly, an interpretation of the mechanism of periodic nanostructures formation on copper thin film induced by picosecond laser was established on the basis of our experimental data, seems relevant to the self-organization theory, particularly, in multi-pulses regime
Fu, Xinghai. „Endommagement laser en régime nanoseconde dans les couches minces de mixtures d'oxydes métalliques et dans les composants microstructurés“. Phd thesis, Aix-Marseille Université, 2012. http://tel.archives-ouvertes.fr/tel-00942171.
Billard, Franck. „Métrologie de l'indice non-linéaire dans les verres en régime nanoseconde, picoseconde et sub-picoseconde“. Phd thesis, Aix-Marseille 3, 2005. http://tel.archives-ouvertes.fr/tel-00011812.
Nous avons développé un modèle numérique permettant d'étudier le signal. Nous montrons que le profil spatial du faisceau avait une grande importance sur la mesure. Ensuite la réalisation expérimentale des bancs comprenant tous les moyens de caractérisation nécessaires à une mesure absolue est détaillée.
Enfin, une étude de l'indice de réfraction non-linéaire de la silice est entreprise pour différents régimes temporels. Une grande dépendance avec la durée des impulsions et l'absence d'effets thermiques sont constatées ainsi qu'une contribution non négligeable de l'électrostriction en nanoseconde.
Frugier, Pierre Antoine. „Quantification 3D d’une surface dynamique par lumière structurée en impulsion nanoseconde. Application à la physique des chocs, du millimètre au décimètre“. Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112129.
A Structured Light System (SLS) is an efficient means to measure a surface topography, as it features both high accuracy and dense spatial sampling in a strict non-invasive way. For these reasons, it became in the past years a technique of reference. The aim of the PhD is to bring this technique to the field of shock physics. Experiments involving shocks are indeed very specific: they only allow single-shot acquisition of extremely short phenomena occurring under a large range of spatial extensions (from a few mm to decimeters). In order to address these difficulties, we have envisioned the use of a well-known high-speed technique: pulsed laser illumination. The first part of the work deals with the evaluation of the key-parameters that have to be taken into account if one wants to get sharp acquisitions. The extensive study demonstrates that speckle effect and depth of field limitation are of particular importance. In this part, we provide an effective way to smooth speckle in nanosecond regime, leaving 14% of residual contrast. Second part introduces an original projective formulation for object-points reconstruction. This geometric approach is rigorous; it doesn’t involve any weak-perspective assumptions or geometric constraints (like camera-projector crossing of optical axis in object space). From this formulation, a calibration procedure is derived; we demonstrate that calibrating any structured-light system can be done by extending the Direct Linear Transformation (DLT) photogrammetric approach to SLS. Finally, we demonstrate that reconstruction uncertainties can be derived from the proposed model in an a priori manner; the accuracy of the reconstruction depends both on the configuration of the instrument and on the object shape itself. We finally introduce a procedure for optimizing the configuration of the instrument in order to lower the uncertainties for a given object. Since depth of field puts a limitation on the lowest measurable field extension, the third part focuses on extending it through pupil coding. We present an original way of designing phase components, based on criteria and metrics defined in Fourier space. The design of a binary annular phase mask is exhibited theoretically and experimentally. This one tolerates a defocus as high as Ψ≥±40 radians, without the need for image processing. We also demonstrate that masks designed with our method can restore extremely high defoci (Ψ≈±100 radians) after processing, hence extending depth of focus by amounts unseen yet. Finally, the fourth part exhibits experimental measurements obtained with the setup in different high-speed regimes and for different scales. It was embedded on LULI2000 high energy laser facility, and allowed measurements of the deformation and dynamic fragmentation of a sample of carbon. Finally, sub-millimetric deformations measured in ultra-high speed regime, on a cylinder of copper under pyrotechnic solicitation are presented
Chambonneau, Maxime. „Etudes multi-longueurs d’onde de l’endommagement laser à la surface de composants optiques en silice en régime nanoseconde“. Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4350/document.
In this thesis, laser-induced damage phenomenon on the surface of fused silica components is investigated in the nanosecond regime. This phenomenon consists in an irreversible modification of the material. In the nanosecond regime, laser damage is tightly correlated to the presence of non-detectable precursor defects which are a consequence of the synthesis and the polishing of the components. In this thesis, we investigate laser damage in a multiple wavelengths configuration. In order to better understand this phenomenon in these conditions of irradiation, three studies are conducted. The first one focuses on damage initiation. The results obtained in the single wavelength configurations highlight a coupling in the multiple wavelengths one. A comparison between the experiments and a model developed during this thesis enables us to improve the knowledge of the fundamental processes involved during this damage phase. Then, we show that post mortem characterizations of damage morphology coupled to an accurate metrology allow us to understand both the nature and also the chronology of the physical mechanisms involved during damage formation. The proposed theoretical scenario is confirmed through various experiments. Finally, we study damage growth in both the single and the multiple wavelengths cases. Once again, this last configuration highlights a coupling between the wavelengths. We show the necessity to account for the spatial characteristics of the laser beams during a growth session
Gouldieff, Céline. „Etude de l'interaction laser-matière en régime nanoseconde sous irradiations multiples : application aux composants optiques pour l’UV“. Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4328.
The work is devoted to laser-induced damage in the nanosecond regime at the wavelengths of 266 nm and 355 nm. The goal of this study is to understand and to analyze the processes taking place during multi-pulse irradiation causing laser-damage, on the surface and in the bulk of massive or thin-films optical materials. To this end, a laser-damage experiment was entirely set up and automated. It allows analyzing the laser-damage resistance and the ageing of these components under UV irradiation at a pulse repetition rate of 50 Hz and for a high number of laser pulses and to record systematically the most important test parameters (spatial beam profiles, energies, images of the site before and after irradiation).To better understand the physical phenomena leading to fatigue effects in the materials under multiple pulse irradiation, a model was developed allowing the discrimination of statistical effects (due to the high number of shots) from material modifications under UV irradiation. This model was confirmed by testing synthetic fused silica irradiated in the bulk. Concerning thin-film coated components, oxide mixtures were studied in collaboration with the Laser Zentrum Hannover (LZH, Germany) using a multi-parameter approach. These materials show indeed a complex behavior and remain poorly known, in particular under multi-pulse irradiation. Finally, a part of the work is dedicated to the non-destructive characterization of KDP crystals by UV-pumped photoluminescence, realized in the framework of the MegaJoule project, in collaboration with CEA Le Ripault (Monts, France)
Olivier, Thomas. „Contribution à la métrologie de l'indice de réfraction et de l'absorption non-linéaires en régime nanoseconde : amélioration de la méthode de Z-scan et simulations numériques“. Phd thesis, 2004. http://tel.archives-ouvertes.fr/tel-00009261.