Dissertations / Theses on the topic 'Laser fibré de haute puissance'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 41 dissertations / theses for your research on the topic 'Laser fibré de haute puissance.'
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.
Gouin, Samuel. "Cavités laser de haute puissance sans épissure." Master's thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/31752.
In a rapidly growing market, high power fiber laser development is key in making this technology available to a large number of industries. Laser manufacturers must constantly develop new methods to upgrade lasers performances and reliability if they want to keep a significant market share. Fiber Bragg gratings (FBG) inscription in a continuous doped fiber segment allows the possibility for a splice less laser cavity, such a laser cavity being more reliable, fasterto build and granting higher laser efficiencies.The experiments demonstrated the feasibility of FBG inscription in an ytterbium doped fiber with a sufficient reflectivity and low enough heating losses to withstand an emission power of 538 W with 77% laser efficiency, the maximum power being currently limited by the available pump power. By extrapolating the data, it is found that the gratings have a low enough heating slope to support a laser emission of 1030 W. The different laser cavities assembled showed that it is very difficult to make a splice less single mode laser cavity in a high brightness fiber, because the injection mode filtering technique cannot be used. However, it has been shown that by using a large mode area fiber (LMA), a splice less single mode laser cavity can be made and that counter-pumping yields the best efficiency. Numerical simulations allowed us to understand that the power distribution inside of the laser creates an uneven heating between the FBG, making extra considerations mandatory to avoid spectral shift between the gratings. The project has shown that it is conceivable to commercialise a splice less laser emitting 1 kW in a near future and that the current available technology would allow such a realisation.
De, Mollerat Du Jeu Rémi. "Développement d'architectures de fibres structurées pour l'amplification d'impulsions haute puissance crête." Thesis, Limoges, 2018. http://www.theses.fr/2018LIMO0033/document.
As part of a CIFRE contract between Thales L.A.S. France and the XLIM laboratory (UMR 7252 of the CNRS and the University of Limoges), my thesis project consists in the development of ytterbium-doped optical fiber architectures for pulses amplification with high peak power at a wavelength of 1 µm in order to achieve a coherent beam combination to obtain a laser source with both a very high peak power and a high repetition rate. Based on a large-core fibre design called FA-LPF, two development axes are addressed. The first one concerns the tolerances improvement to an external bending applied on the FA-LPF. With the help of a numerical study, an innovative strategy is implemented to mitigate the effects of bending. The architecture is then called step-index assisted FA-LPF. A single a singlemode laser emission in continuous regime with an optical power of 65 W is demonstrated with a 60 cm bending radius for a 47 µm mode field diameter. The second axis is the implementation of the polarisation control in FA-LPFs. The goal is to obtain a linearly polarised signal. Several numerically tested architectures allow single linear polarisation propagation in passive structures over a broadband optical spectrum, including a singlemode single-polarisation propagation at 1400nm for a core diameter of 140 µm. The best architecture, called FA-LPF 4+2 SAP, is fabricated with active ytterbium dopants. Due to manufacturing defects, the obtained fibres act as polarisation maintaining fibres. A polarisation extinction ratio of 17 dB is obtained in an amplification configuration in continuous regime with 24 dB of gain (an emitted power of 50 W)
Mollerat, du Jeu Rémi de. "Développement d'architectures de fibres structurées pour l'amplification d'impulsions haute puissance crête." Electronic Thesis or Diss., Limoges, 2018. http://www.theses.fr/2018LIMO0033.
As part of a CIFRE contract between Thales L.A.S. France and the XLIM laboratory (UMR 7252 of the CNRS and the University of Limoges), my thesis project consists in the development of ytterbium-doped optical fiber architectures for pulses amplification with high peak power at a wavelength of 1 µm in order to achieve a coherent beam combination to obtain a laser source with both a very high peak power and a high repetition rate. Based on a large-core fibre design called FA-LPF, two development axes are addressed. The first one concerns the tolerances improvement to an external bending applied on the FA-LPF. With the help of a numerical study, an innovative strategy is implemented to mitigate the effects of bending. The architecture is then called step-index assisted FA-LPF. A single a singlemode laser emission in continuous regime with an optical power of 65 W is demonstrated with a 60 cm bending radius for a 47 µm mode field diameter. The second axis is the implementation of the polarisation control in FA-LPFs. The goal is to obtain a linearly polarised signal. Several numerically tested architectures allow single linear polarisation propagation in passive structures over a broadband optical spectrum, including a singlemode single-polarisation propagation at 1400nm for a core diameter of 140 µm. The best architecture, called FA-LPF 4+2 SAP, is fabricated with active ytterbium dopants. Due to manufacturing defects, the obtained fibres act as polarisation maintaining fibres. A polarisation extinction ratio of 17 dB is obtained in an amplification configuration in continuous regime with 24 dB of gain (an emitted power of 50 W)
Grande, Adrian. "Laser à fibres Tm : Ho de haute puissance à femtoseconde à 2050 nm." Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0021.
The chirped pulse amplification (CPA) technique was developed to power scale the pulsesfrom mode-locked oscillators as the pulse energy was not sufficient to target applicationssuch as strong field physics and particle acceleration. Since its development in 1985 ithas been applied in a wide variety of commercially available laser systems and ultra-highpower laser facilities. The technique allows to circumvent the accumulation of non-linearphase which hampers pulse compression and allows to maintain the fluence of the pulsesbelow the laser induced damage thresholds (LIDT) of components. In this thesis wedevelop CPA laser systems operating at 2.05μm wavelengths with high average powerand high energy starting from the development of the seed laser up to the design andimplementation of the pulse stretcher, amplifiers and pulse compressor.In the first section of the thesis we introduce the physics background and phenomenarequired for understanding the chirped pulse amplification technique and the developmentof the seed laser. This includes dispersion, self-phase modulation and Raman scattering.In the second section of the thesis we present the development of an all-fiber polarizationmaintaining laser tunable over 170nm, from 1880nm up to 2050nm via Ramansoliton self-frequency shift (SSFS). The system is based on exclusively commercially availablestandard fibers. We have characterised the laser in terms of power, spectrum andpulse duration and we have included a post-compression stage that relies on non-lineareffects to reach the sub-100 fs duration across the whole tunability range. Simulations ofthe soliton post-compression shows the versatility of the laser which allows to customisethe pulse duration over a spectral range or for a particular wavelength. We believe thatthe laser is a versatile and robust alternative to Tm and Tm:Ho oscillators.In the third section we have tested the tunable laser in a wide variety of stretchingand compression architectures suitable for CPA. We have investigated fibers and chirpedvolume Bragg gratings (CVBG) as pulse stretching devices and grating pairs and CVBGsas pulse compressors. We discuss how to dimension a stretching-compressor pair takinginto account the non-linear phase and gain narrowing effect that takes place during pulseamplification and how to evaluate the stretching-compressor performance. Two differentchirped pulse amplification laser systems have been designed and presented, the first onetargets broadband fs pulses with high average power and the second system targets highenergetic ps pulses. The non-mature technology in the 2μm spectral region and the weakavailability of suitable stretching devices hinders pulse compression at this wavelength.In the last section of the thesis we investigated the performance of Tm:Ho co-dopedfibers in amplification configuration. We discuss the main challenges of these fibers includingthe cross-relaxation effects, the availability of pump sources which gives rise totwo main pumping schemes: diode pumping and in-band pumping and the limitations interms of fiber size. We tested Tm:Ho doped fibers, including LMA for narrowband andbroadband pulse amplification
Brown, Dussault Evelyne. "Atténuation d'effets non linéaires dans les lasers fibrés de haute puissance opérés en régime continu." Master's thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/27006.
High power fiber lasers are now the preferred solution when it comes to industrial cutting applications. Development and power scaling of industrial grade high power fiber lasers is however limited by industrial reliability specifications. Power scaling of fiber lasers is limited by non-linear effects, which arise from fiber designs with a small mode area therefore requiring the development of new methods to suppress non-linear effects. In this memoir, experiments and simulations show that the models used to describe nonlinear effects in the case of passive fibers are no longer valid in the case of high power fiber lasers. New metrics must thus be defined. We also show that the laser configuration influences the non-linear effects. Using the general non linear Schrödinger equation we also show that in the case of a high power end-pumped laser configuration, Raman scattering affects spectral broadening. Experimental and theoretical work also show that changing the grating mirror properties such as increasing the reflectivity or the bandwidth of the low reflectivity grating reduces Raman scattering.
Guiraud, Germain. "Développement de sources laser à fibres dopées ytterbium haute puissance, monofréquence et à bas bruit d'intensité." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0648.
High power, narrow linewidth fiber lasers are useful for both industrial and scientific applications. Nevertheless, nonlinear effects like Stimulated Brillouin Scattering (SBS) are main limitations of these laser sources due to high power in fiber core. A first amplifier in single-frequency operation with 50W of output power from a laser diode seeder of 50 mW was developed. Study of intensity noise on this amplifier developed with standard fiber (core diameter less than 20 μm) showed that SBS leads to a degradation of noise properties of the laser. The use of large mode area (LMA) fibers is a solution for suppressing nonlinear effects with core diameters bigger than several tens of microns. LMA fibers show an overlap between doped core and pump wave optimized leading to a reduction of gain medium length. This strategy permits to increase nonlinear effect threshold. Second step of high power amplifiers with LMA fibers allows to obtain 100W in single-frequency regime without DBS. LMA fiber used have a core diameter equals to 40μm. Power scaling from 100W to 200W highlights a new limiting non-linear effect: Fiber Modal Degradation (FMD). Indeed, multimodal cores of these fibers, coupled to high thermal load lead to non-linear effects like Modal Instabilities (IM) and FMD. FMD effect, first described by Ward et al in 2016, is a thermo-optic effect characterized by a beam quality degradation with power transfer from fundamental mode to high order modes. Furthermore, a decrease of output power, synonym of guidance loss of fundamental mode in gain medium is observed. Unlike well-known effect IM, this phenomenon doesn’t act like a threshold phenomenon. In fact, transitory regime in association with FMD is longer than IM caused by photodarkening dynamic. In our study, beam quality at the output of the fiber was degraded after several tens of hours at 200W. For understanding this effect, a photodarkening effect study both in continuous wave (CW) and pulsed regime was carried out. This study shows that for the first time a photodarkening and photobleaching equilibrium on high power amplifiers in pulsed regime. These thermo-induced effects threshold depends on thermal load and are different for both regimes: 120W for CW and 150W for pulsed regime. Finally, a study and a reduction of intensity noise based from a servo-loop were carried out on 100W amplifier. A 1MHz bandwidth with a 30 dB decrease of noise were demonstrated. These results allow to develop high power and low intensity noise lasers at industrial level”
Benoit, Aurélien. "Sources laser fibrées hybrides de haute puissance : Amplification et conversion de fréquences." Thesis, Limoges, 2015. http://www.theses.fr/2015LIMO0024/document.
High-power fiber lasers adress an increasing number of applications since ten years. In the frame of a CIFRE contract between the company Eolite Systems and Xlim (joint laboratory between CNRS and the University of Limoges), the goal of this PhD project was to develop the technological blocs to achieve all-fibre high-power lasers emiting out of the conventional spectral band covered by existing lasers.Modal instabilities in large mode area (LMA) fibers are currently the main limitation of the fiber lasers power scaling. We have experimentally demonstrated the relevance of inner cladding aperiodic structures to efficiently delocalize higher order modes outside the gain region. A systematic study of passive fibers based on such structures has shown the single propagation of the fundamental mode over a wide wavelength range from 1 to 2 µm for dimension of core up to 85 µm. This effective mode delocalization even extends up to a core dimension of 140 µm at a 2 µm wavelength.The combination of high power picosecond fiber laser with an average power of 22.7 W and a hydrogen-filled inhibited coupling Kagome fiber allowed us to generate two Raman combs over five frequency octaves from 321 nm to 12.5 µm. These two combs are controlled by the laser pump polarization and generated an average power of 10.1 W displayed over 70 laser lines for circular pump polarization and 8.6 W over 30 lines for linear polarization. Some laser lines within these combs have been generated for the first time from high-power fiber source in the mid-infrared range. We have also demonstrated the generation of high-power line by optimizing the first vibrational Stokes at 1.8 µm with an average power of 9.3 W and a quantum efficiency of the frequency conversion stage close to 80%
Wei, Li-Wei. "Système laser de haute-puissance pour le projet Advanced Virgo : les amplificateurs à fibre combinés de façon cohérente." Thesis, Nice, 2015. http://www.theses.fr/2015NICE4091/document.
Virgo is a cavity-enhanced Michelson interferometer built for the direct detection of gravitational waves. The Advanced Virgo project consists of major upgrades to the Virgo gravitational wave detector for an order of magnitude improvement in differential strain sensitivity, one of which is the tenfold increase in injected laser power to 175 Watts. The use of fiber laser amplifiers and their coherent combination are foreseen to deliver the required high-power low-noise beam. In this thesis work, we review the laser requirements for gravitational wave detectors, introduce the design of the laser system for Advanced Virgo, and develop the means for laser characterization in accordance with the stringent noise specifications. We then present the results to date, notably the quasi-continuous long-term operation of two 40-Watt fiber laser amplifiers over thousands of hours and their coherent combination with Mach-Zehnder interferometry. Although the targeted power for Advanced Virgo is not yet attained, the developed system shows decent noise performance and is promising for further power-scaling efforts
Abbouab, Clara. "Étude et conception de sources laser fibrées monomodes en régime continu multi-kW." Electronic Thesis or Diss., Limoges, 2023. http://www.theses.fr/2023LIMO0088.
This CIFRE thesis is a collaboration between the XLIM research laboratory and the industrial laser company "CILAS". The main objective of this work is to study and design high power fiber laser sources delivering a continuous wave single mode laser beam with an output power of several kW. To this end, the “MOPA” design (consisting a master oscillator stage and a power amplifier stage) was chosen from the literature and then has been built at XLIM. To the best of our knowledge, it is the first time in France that 2 kW of continuous wave output power has been achieved at the signal wavelength of 1080 nm. Thanks to the experimental results, a simulation tool was calibrated and used to carry out a theoretical study of the limits of this laser source. This tool has also been used to propose some improvements of this architecture by changing the pump wavelength, the signal wavelength, the doped fiber and the combination of the pump power between the two directions of propagation. The results of the simulations were compared with the experimental results obtained from a new source reaching more than 3 kW of continuous wave power. Finally, another less complex design, called OAIFL, was calibrated using the simulation and then built. A supercontinuum was generated by exploiting the temporally unstable laser cavity, delivering a power of 40.7 W over a spectrum going from 750 nm to 2200 nm at - 30 dB. As a perspective, the simulation showed that the OAIFL source could be further amplified to reach up to 3 kW. Therefore, this laser source could be further developed in the future
Ghawas, Muhammad. "Sources picosecondes et femtosecondes à base de fibre dopées Ytterbium et applications." Electronic Thesis or Diss., Bordeaux, 2023. http://www.theses.fr/2023BORD0463.
Ultrashort laser pulses in both industrial and research applications progressively rely on fiber laser technology, guided by its intrinsic benefits, for instance, stability, compact nature, excellent beam quality, robustness, and easy operation. In this work, a detailed study has been done to investigate picosecond fiber laser working in an all-normal-dispersion (ANDi) regime for the application of parametric generation in photonic crystal fiber. In summary, we have developed a high-power fiber laser source delivering picosecond pulses with tunability both in central wavelength and spectral width. It incorporates a combination of a large-mode-area rod-type ytterbium fiber, a slit, and a transmission grating inside the ring laser cavity configuration. At the central wavelength of ∼ 1030 nm and with a repetition of 78 MHz, this laser delivers picosecond pulses with an average power of up to 25 W. The pulse duration can be continuously adjusted from ∼ 1.8 ps to ∼ 4.5 ps and pulse energy from ∼ 320 nJ and ∼ 225 nJ, respectively. Additionally, we have also demonstrated that the central wavelength of the laser pulse can be finely tuned from ∼ 1010 nm to ∼ 1060 nm while keeping the pulse energy above ∼ 150 nJ. We have also proposed a numerical model to account for the ensemble of our experimental data and the simulations are in good agreement with the experimental data. The output of this fiber oscillator is propagated through the photonic crystal fiber for the parametric generation of the signal (higher frequencies than the pump) and idler (lower frequencies than the pump). The fiber OPO singly-resonant cavity was built in such a way that only signal wavelengths are allowed to propagate through it. The conversion efficiency for the signal was close to 20 % in the fiber OPO. Based on the dispersion profile of the photonic crystal fiber and our homebuilt tunable pump laser, the signal wavelength (resp. idler) was tuned from ∼ 770 nm to ∼ 1000 nm (∼ 1130 nm to ∼ 1590nm) for the corresponding pump wavelengths of ∼ 1024 nm to ∼ 1059 nm
Machinet, Guillaume. "Développement de sources lasers femtosecondes ytterbium à très haute cadence et applications." Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR14999/document.
This work concerns the development of high repetition rate femtosecond lasers with high average power (>10 W)and energies in excess of 100 μJ. Such lasers are paramount for the development of new industrial applications(athermal micro-drilling, eye surgery, ...) and for fundamental research on high repetition rate laser matter interactionstudies.After a brief introduction and the state of the art summary on high-average power femtosecond laser with ytterbiumdoped materials, a compact high-average power femtosecond laser with a large mode area microstructured rod typeamplifier will be presented. It will browse the main limitations in terms of energy and average power. Limitationsare mainly due to the strong confinement of the electric field propagating in the fibre core leading to non-linear effectsaccumulated during the amplification. On the other hand, for larger core diameter (> 70 μm), the fundamental modeguiding (TEM00) is very weak and thus very sensitive to the internal thermal load of the fibre.This laser source has been used in two specific applications: athermal drilling of thick stainless steel plate for mineclearing(an application of interest for the Direction Générale de l’Armement) and High order Harmonics Generationat high repetition rate (related to CELIA activities). These two applications are presented in the third chapter.In order to stretch the limits and generate more energetic and a shorter pulse, a new amplification scheme has beenproposed, namely high brightness optical pumping of ytterbium doped materials. This concept presented in the lastchapter benefits from the development of high average power single-mode fibre lasers source emitting at 976 nm.This amplification scheme allowed us to realize a high average power Kerr-lens oscillator delivering pulses with apulse duration below than 70 fs and an average power of 2.3W at a repetition rate of 73 MHz. In a second phase, wealso developed a « booster » amplifier with a high single- pass-gain. These two results have been obtained by usingYb-doped CaF2 crystals. This material presents the advantage to have a very broad emission bandwidth (> 60nm)suitable to generate and amplify femtosecond pulses and to be compatible with high average power laser due to hisvery good thermal conductivity
Tang, Mincheng. "Etude du comportement dynamique des sources laser ultrarapides à base de fibres actives fortement dispersives." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMR117/document.
Ultrafast fiber lasers represent today a ubiquitous technology in various industrial and research applications thanks to their inherent advantages such as compactness, stability and high power. The best performances to date, mostly relying on large mode area fibers and chirped pulse amplification, however require complex experimental developments and are limited by the use of bulk components for pulse stretching and compression. The experimental and numerical work presented in this PhD thesis aimed at exploring original dynamical regimes based on specific active fibers combining large mode area and high dispersions for the generation of high-energy ultra-short pulses. The numerical studies then showed that pulsed regimes with high normal dispersions could be reached by exploiting resonance and mode-coupling phenomena in Bragg or W-type fibers. Studying the influence of the cavity parameters on mode-locking mechanisms allowed to target attractive configurations for energy scaling. The experimental implementation of this concept allowed the development of a dissipative soliton source delivering record high-energy chirped pulses (38 nJ, 700 fs after compression) at 1560 nm. The realization of ultrafast sources based on specific active fibers combined to mode-coupling phenomena then brought the possibility to identify the potentiality and limitations of these particular architectures with high dispersions for energy scaling
Pariente, Gustave. "Caractérisation spatio-temporelle d’impulsions laser de haute puissance." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS003/document.
High power laser make it possible to reach very high intensities (up to 10²²W.cm⁻²). In order to get to this level of intensity, a moderate quantity of energy (on the order of the Joule) is concentrated in a very short time (on the order of tens of femtoseconds) onto a small surface (on the order of 1 μm²). These beams are therefore ultra-short and focused with a high aperture optic. These features mean that their diameter prior to focus is large and their spectral width is big. As a result, these beams are subject to spatio-spectral distorsions (of spatio-temporal couplings). After focus, these distorsions induce a dramatic reduction of the peak intensity. This situation is all the more true when the laser is more intense and its diameter and spectral width are therefore bigger. Despite their detrimental effects, spatio-temporal couplings can be of great interest when controlled. One can indeed introduce weak spatio-temporal couplings for experimental purposes. In the 1990s and 2000s, a big effort was put in order to characterize dans optimize the temporal profile of femtosecond lasers. Meanwhile, adaptative optics solutions were developed to control the spatial profil of ultra intense laser beams and provide the best focal spot achievable. By nature, this approach is blind to spatio-temporal couplings. Measuring these distorsions requires a spatio-temporal characterization. Before the start of this Phd thesis, spatio-temporal characterization methods already existed. Although none of these devices were ever adapted to the measurement of ultra-intense laser beams. During this Phd Thesis, we developped a new spatio-temporal characterization technique which we called TERMITES. This technique is based on a self-referenced Fourier transform spectroscopy scheme. TERMITES made it possible for us to perform the first total spatio-temporal characterization of a 100 TW laser (UHI-100 at CEA Saclay, France). The detection of spatio-temporal distorsions with the help of these measurements confirmed the need for a generalization of spatio-temporal characterization of ultra-high power lasers
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
Hazera, Christophe. "NOPCPA ultracourt pompé par CPA fibré haute cadence." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0094/document.
In recent years, the development of femtosecond lasers has been heavily oriented towards high average power sources forboth scientific experiments - such as XUV pulses generation - as well as for industrial applications. This work has been devoted to developa laser source able to amplify ultra-short pulses at a very high repetition rate. In one hand, we develop a high average power (50W)pump laser based on a Fiber Chirped Pulse Amplification (FCPA) technology delivering 400 fs pulses at a high repetition rate (100kHz).In the other hand, a multistage ultrafast optical parametric amplifiers (<10fs) pumped by this source has been then implemented. Toachieve this, we took the benefits of the Ytterbium-doped large-core photonics fibre’s properties in order to approach energies closeto 1mJ. Even in a highly stretched chirped pulse architecture (2ns), using this kind of technology, required to perform studies overdamage and preparation processes of fibers. Thereby, we demonstrated a maximum output power of 90W, but excellent results havebeen obtained in a stable and robust regime in which this laser delivers 60W with pulse durations shorter than 400fs. After frequencydoubling, this laser was sent as a pump into a two-stages - non collinear parametric amplifier made with BBO crystals and a spectrumdelivered a by a CEP-Stable-6fs Ti :sa oscillator has been amplified around 800nm over a spectral bandwidth larger than 300nm witha pulse energy of 19[mu] J (1.9W). By using a stretching and compression scheme based on the combination of silica wedges and chirpedmirrors, the final pulses have been then recompressed down to 9.7fs. These laser systems can be now used to pave the way for vast fieldsof investigation in molecular and atomic physics
Huneault, Mathieu. "Investigation numérique de l'instabilité Raman dans les lasers à fibre optique dopée à l'ytterbium en régime continu de haute puissance." Master's thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/34745.
Continuous high-power ytterbium-doped fiber lasers have an increasing market share formetal processing applications. Despite their widespread use, these lasers still suffer a ma-jor problem. At high power, stimulated Raman scattering shifts the power from the main emission wavelength around 1070 nm to the first Raman Stokes sideband around 1120 nm. This process is called Raman instability. The shifted power becomes useless and can even be dangerous for both the laser system and its users. Previous experimental and theoretical analyses have failed to provide clear explanations on the link between the Raman instability and the parameters of the ytterbium-doped optical fiber and the fiber Bragg gratings forming the laser cavity. The goal of this master’s degree project was to develop a simulation model for continuous high-power ytterbium-doped fiber lasers in order to identify and understand how the parameters of the laser cavity affect the Raman instability and to find cavity configurations that reduce it. This master’s thesis presents the two simulation models developed during this project. The first model considers unidirectionnal propagation of the laser signal while the second one considers bidirectionnal propagation. The latter is thus a more realistic model of such lasers.The typical simulated setup is made of a double-clad ytterbium-doped fiber with a large mode area, a high reflectivity Bragg grating and a low reflectivity Bragg grating that isused as output coupler. The simulations allowed to identify five cavity parameters having an impact on the Raman instability. A low average power, a short gain fiber, a counter-propagation pumping setup as well as a low reflectivity and a large reflective bandwidth for the fiber Bragg grating used as the output coupler help minimizing the Raman instability.The optimisation of these parameters creates a laser cavity with an extremely low power shift to the Raman Stokes sideband. The low Raman instability seems to be caused by a lower intra-cavity power, a shorter propagation distance and fast power modulations in thesignal. Incorporating a filter in the cavity, using a nonlinear reflector as output coupler or using a setup that includes a low-power master oscillator in combination with a high-power amplifier have also been simulated and show a reduction of the Raman instability.
Tiabi, Nadia. "Synthèse de préformes dopées ytterbium par voie poudre pour la réalisation des lasers à fibre de haute puissance." Electronic Thesis or Diss., Limoges, 2023. http://www.theses.fr/2023LIMO0049.
The work presented in this manuscript is part of a PhD thesis carried out by CIFRE in collabora-tion between the laboratory of Xlim and the technological center of optics and lasers "ALPhA-NOV". The main objective of this thesis is to design ytterbium doped preforms that are resistant to the photodarkening (PD) phenomenon for use in high power laser applications.This phenomenon degrades laser performance and leads to reduced output. Two main areas are focused in this thesis. The first is the definition of the core composition and the appropriate synthesis method for the production of preform cores which are resistant to photodarkening (PD). The second is to develop, characterize and evaluate the optical performance of the resulting fiber. The matrix that has been chosen for the study is the alumino-phosphosilicate matrix. To obtain this matrix, a synthesis method called "powder in suspension" was used.From the synthesis of the preform to the drawing of the optical fiber, the different stages of the process have been validated. Excellent performance, with low attenuation of 0.1 dB/m and a very promising optical-to-optical conversion efficiency of 76%, was obtained from the optical tests performed on the fiber. The evaluation of the fiber against photodarkening showed an exceptional resistance. No performance degradation was observed over 100 hours
Delaigue, Martin. "Étude et réalisation de sources femtosecondes haute puissance moyenne." Bordeaux 1, 2006. http://www.theses.fr/2006BOR13217.
Baubeau, Emmanuel. "Etude et réalisation d'une chaine laser femtoseconde haute cadence de haute puissance moyenne : applications au micro-usinage." Paris 11, 2002. http://www.theses.fr/2002PA112326.
Since the early 90's, much progress has been done in the field of ultrashort laser sources, mostly based on Ti:sapphire crystals. The shortest pulse duration and the highest energy were the main goals of these developments. In the same time, few work has been done on high-repetition rate sources (more than ten kilohertz). The first part of this work is dedicated to the study of a 15 kHz femtoseconde laser source with high average power. The pump laser is a 100-W Hybrid copper vapour laser. Thermal effects inside the crystals are carefully studied as well as the design of a regenerative cavity and multi-pass amplifiers taking into account these thermal problems. The second part deals with a particular application of these high-repetition rate sources: micro-machining. Experimental results are shown, mostly on metals. To have a comprehensive approach of the specificity of laser-matter in the femtosecond regime, a two-temperature model is developped. It leads to a simulation of the thermal diffusion length, bath axially and radially. The results shows a striking difference between nanosecond and femtosecond regime
Gallet, Valentin. "Dispositifs expérimentaux pour la caractérisation spatio-temporelle de chaines laser femtosecondes haute-puissance." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112189/document.
One of the advantages of high-power femtosecond lasers (TW-PW) is to obtain, at the focus of a focusing optic, very high intensities up to 10^22W.cm^-2 (i.e. an electric field of 2.7 PV.m^-1. Therefore, these lasers chains necessarily deliver beams with large diameter (up to 40 cm) and very short pulses (of the order of tens of femtoseconds). As a consequence, the spatial and temporal properties of the pulse are generally not independent. Such dependence, called spatial-temporal coupling has the effect of increasing the pulse duration and the size of the focal spot, which can lead to a significant reduction of the maximum intensity at the focus. Metrology devices commonly used on these high-power femtosecond lasers allow retriving the spatial and temporal profiles of the pulse only in an independent manner. The aim of this thesis was to develop techniques for measuring spatiotemporal couplings in order to quantify their effect and correct them in order to obtain the maximum intensity at focus. First of all, we adapted an existing technique of spatio-temporal characterization to the measurement of TW lasers. To avoid the issues induced at the focus, such as those related to jittering, measurements were performed on the collimated beam. By adding a reference source to the original device, we managed to take into account the measurement artifacts due to thermal and mechanical variations affecting the interferometer. With this improvement, it was possible to reconstruct the complete spatio-temporal profile of the beam, particularly its wavefront. However, the limitations imposed by this technique led to the development of a new measurement device. Based on a cross-correlation, this technique consists of making the laser beam to interfere with a part of itself, small enough not to be spatiotemporally distorted. We have also implemented a variant of this device for a single-shot measurement along one transverse dimension of the pulse. Using these techniques, we performed the very first characterization of several TW laser chains. The measurements have revealed the existence of residual space-time couplings leading to a significant decrease of the peak intensity at focus. These results show that it is essential to spatio-temporally characterize high power femtosecond laser chains to obtain the maximum intensity at focus
Sellahi, Mohamed. "Laser à semi-conducteur III-V à émission verticale de haute cohérence et de forte puissance : état vortex, continuum et bifréquence THz." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20212/document.
The work presented in this thesis is based on the expertise of the VECSEL group of the Institut d'Électronique de Sud (IES) in the design, implementation and study of VECSEL in the near and mid infrared. Before engaging in the work presented here, the VeCSELs developed in our laboratory involved the usual single-frequency operation with a TEM 00 beam, but pushed to high power and high coherence. The objective of this thesis is to go beyond this conventional state and to explore other coherent states of the photon, unusual in the field of laser emission. These new states apply to both the transverse appearance (spatial) and longitudinal (time) of the wave. More specifically, the laser emission of high power and high coherence on the Laguerre-Gauss higher order modes degenerate and non-degenerate (optical vortex), and the wide band coherent lasers also called "modeless lasers"
Seang, Chansopheak. "Evaluation numérique des contraintes résiduelles appliquée à l'acier DP600 soudé par laser de haute puissance Nd : YAG." Phd thesis, INSA de Rennes, 2013. http://tel.archives-ouvertes.fr/tel-00875121.
Delmas, Olivier. "Étude de la mise en forme temporelle d’impulsions laser de haute puissance pour l’excitation des sources laser X-UV sur la plateforme LASERIX." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS277/document.
The thesis fits within the framework ofsoft x-ray lasers (SXRL) development and has formain objective to study the influence of the temporal shaping of ultra-intense laser pulses, on the efficiency of SXRL generation. My thesiswork consisted in studying, designing and calibrating new pumping schemes through various devices based on the prepulse generation and/or an amount of ASE within the laser driver.In this manuscript, I study their influence on the SXRL generation efficiency by highlighting the optimization parameters such as the delay and the energy ratio between pulses, or the duration of each of them. The experimental study highlights first of all the influence of a prepulse on the SXRL generation efficiency. In the same framework, a device was experimented, allowing to generate within a single laser beam two mainpulses preceded by a prepulse, while maintaining a control over their spectro-temporalcharacteristics.An alternative approach was experimented in which an additional low cost « Q-Switch » lase rwas used to produce a under dense plasma presenting smooth electronic density gradients.This last device has showed excellent performances on a wide wavelength range andhas been used to perfom an experiment of highorder harmonic seeding generated from an Argongas cell on the secondary LASERIX beamline. A noteworthy improvement of the spatial characteristics and the temporal coherence of theSXRL have been observed
Haddad, Kamal al. "Étude des différentes stratégies de contrôle d'un convertisseur à résonance : application à l'alimentation haute tension d'un laser CO2." Toulouse, INPT, 1988. http://www.theses.fr/1988INPT008H.
Albach, Daniel. "Gestion de l'émission spontanée amplifiée et de la thermique d'un système laser solide de haute puissance moyenne pompée par diodes – le système laser Lucia." Phd thesis, Ecole Polytechnique X, 2010. http://tel.archives-ouvertes.fr/tel-00504915.
Hernandez, Jacques. "Etude de structures bi-métalliques réalisées à l'aide de faisceaux de haute énergie (plasma PTA, laser) : détermination et modélisation des contraintes résiduelles." Lyon, INSA, 1986. http://www.theses.fr/1986ISAL0020.
Laurain, Alexandre. "Sources laser à semiconducteur à émission verticale de haute cohérence et de forte puissance dans le proche et le moyen infrarouge." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2010. http://tel.archives-ouvertes.fr/tel-00613743.
Cantin, Etienne. "Cavité à haute finesse pour la production et la détection de sources atomiques cohérentes." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0259/document.
This thesis reports the development of two original tools for atom interferometry.The first is a high finesse optical cavity for the manipulation of 87Rb cold atoms. This cavity isfirstly used to enhance the intensity of an optical dipole trap. Thus, by realizing an evaporativecooling on the atomic sample, we reached Bose-Einstein condensation. Furthermore, the nondegeneratecavity allows the injection of different transverse electromagnetic modes. In thisway, we have demonstrated the generation and the manipulation of arrays of atomic ensemblesusing these modes. Successive measurements of these atomic ensembles in an atominterferometric sequence would increase the interrogation time and thus the sensitivity of thesensor.Secondly, the use of weak nondestructive measurements on the atoms allows to extractinformation from the system with negligible perturbation of the ensemble. Applying feedbackafter the measurement, we were able to control the quantum state of the system. Using amodified Ramsey sequence with weak nondestructive measurements and phase corrections, werealized a phase lock loop between a local oscillator and the atomic state. We have thendemonstrated that this protocol leads to a stability enhancement of an atomic clock byovercoming the limit set by the local oscillator.We also contributed to the development of the commercial laser platform EYLSA fromQuantel, testing its performances on two laser cooling experiments
Nadeau, Marie-christine. "Oscillateurs picosecondes de forte puissance moyenne à faibles bruits." Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14137/document.
For medical or cultural heritage applications, a compact, monochromatic, Compton x-ray source system needs a powerful, few picosecond laser source. To obtain high-x-ray-flux, the laser should be coupled to a high-finesse Fabry-Perot cavity to reach the required laser power. Therefore, the laser should have a good beam quality and low noises. In order to reach theses requirements, we have studied passive mode-locking oscillators delivering more than 10 W average power and between 10 and 20 ps pulse duration.Two high-power oscillators have been designed and implemented: a side-pumped Nd:YAG and an end-pumped Nd:YVO4 oscillator. With the second oscillator, we have studied the experimental reduction of pulse duration. We obtained a decrease from 46 ps to 12 ps in the continuous-wave mode-locked regime. Those experimental results have been explained by a numerical simulation and furthermore, we have developed an analytical solution to predict the pulse duration of such oscillator. Finally, we studied the noise characteristics of the Nd:YVO4 oscillator. Our measurements have shown that a high-power oscillator might be as low-noise as other low-power, low-noise oscillators. In conclusion, we have developed a powerful (20W), 1064nm-wavelength, short-pulses (15ps), good-beam-quality (M2<1.2) and low-noise free-running oscillator (timing jitter <1.2 ps RMS 100Hz-1MHz). Therefore, our high-power oscillator is an excellent candidate to be part of a compact, high-flux, monochromatic x-ray source
Loiseleur, Pierre. "Micro-sources X-UV incohérente et cohérente par décharge capillaire ultra-rapide." Phd thesis, Ecole Polytechnique X, 2004. http://pastel.archives-ouvertes.fr/pastel-00000829.
Pouysegur, Julien. "Amplification d'impulsions femtosecondes dans des amplificateurs à base de cristaux dopés Ytterbium." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLO005/document.
The development of laser sources delivering femtosecond pulses at high repetition rate is one of the main axe of reaserch of these 10 past years and is a key for many industrial and scientific applications. In one hand, fiber lasers allow to reach high average power sources, but the strong confinment of the light leads to high nonlinearities limiting output pulse energy. In the other hand, bulk amplifiers cannot provide as short pulse duration as fiber lasers because of crystals spectroscopic properties. However they can reach higher energy. Usually nonlinear effects are deletarious and limit output temporal pulse quality. A technic to tailor and exploid positively these nonlinearities in order to obtain shorter pulses together with high pulse energy in bulk regenerative amplifier is presented in this thesis.Negative dispersion managment prior amplification permits to precompensate the amplifier positive dispersion together with the accumulated nonlinear phase aquired during amplification. In order to deliver ultrashort pulses with an excellent temporal quality theoritical studies have been carried out to optimise the paramaters. By considering dispersion, nonlinearities and limited gain bandwidth, we could demonstrated sub-100 fs pulses with a peak power of hundreds of MW. These results established new pulse duration record in high gain (50 dB) bulk amplifiers.Another study allowed to design new amplifier geometries for power scaling. This has been done by using slab crystal geometry to improved heat dissipation. More than 60W average power has been demonstrated, highlighting the potential of such architecture for high power lasers. We also studied limitations of such design, especially thermal degradation effects, which are one of the main issues of high power bulk amplifier.5 articles have been written thanks to these theoritical and experimental results and have been presented in 10 conferences. As industrial results Amplitude Systemes has lunched into market two new lines of products: a compact and all integrated laser and a TANGOR 100 W
Decup, Michaël. "Impact des procédés industriels de traitement sur les propriétés diélectriques des substrats d'Alumine utilisés dans les modules de commutation haute tension." Phd thesis, Université Paul Sabatier - Toulouse III, 2010. http://tel.archives-ouvertes.fr/tel-00567179.
Sow, Papa lat tabara. "Développement d'un spectromètre laser à cascade quantique pour des applications en spectroscopie de haute résolution et en métrologie des fréquences." Thesis, Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCD011/document.
This thesis is devoted to the developpement of a laser spectrometer quantum cascade to frequency metrology and high-resolution spectroscopy. The objective of this work is to developp a new tool for projects in our group : Measuring the Boltzman constant and test of non conservation of parity. Thus the new source was characterized by measuring its spectral density noise, amplitude noise and its emission line width. The phase locking of the QCL on the CO2 laser has achived spectroscopy NH and MTO, molecules of interest for the projects of the group mentioned aboive respectively
Bonamis, Guillaume. "Conception et réalisation d’une source laser femtoseconde GHz et applications au régime d’ablation très haute cadence." Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0293.
These last two decades, femtosecond laser technology has gained considerably in terms of maturity and reliability. These laser pulses enable materials micro-machining with minimal thermal collateral effects, thus allowing to work with an outstanding precision, even on materials highly sensitive to temperature. Nevertheless, the penetration of femtosecond processing into the industrial manufacturing market is limited due to an insufficient productivity. The current strategies consist of optimizing the processes on the one hand and increasing the average power of these laser sources on the other hand. Another way suggests increasing the femtosecond ablation process efficiency by delivering bursts of low-energy pulses instead of one highly energetic pulse.Recent works showed that using bursts of pulses at repetition rates on the order of GHz allows to reach ablation rates one order of magnitude higher than the ones obtained by standard femtosecond pulse machining. Nevertheless, these promising results are controversial, as other works point out levels of efficiency lower than expected, added to collateral thermal damages on the machined materials. A thorough study of this new ablation regime is thus necessary to ensure that its interest is justified on the one hand, and to point out the optimal configurations of its use on the other hand. Several optical oscillators delivering bursts of femtosecond pulses at GHz-level repetition rates and laser amplifiers have been developed to this purpose. These innovating laser systems benefit from great flexibility in terms of reachable laser parameters (pulse repetition rate and energy, number of pulses per burst notably). This flexibility allowed us to perform a thorough study of the GHz-ablation regime by numerous machining experiments on several materials of industrial interest. This study points out the influence of the different laser parameters and thus to explain the variety of results related to GHz-ablation and to guide the use of this regime under favorable conditions to reach an efficient and high-quality machining
Montmerle, Bonnefois Aurélie. "Etude théorique et expérimentale d'un laser à solide de forte puissance moyenne, déclenché à haute-cadence et possédant une bonne qualité de faisceau." Paris 11, 2006. http://www.theses.fr/2006PA112069.
The aim of this work is to design, study, understand and optimize a high-repetition-rate (7 to 10 kHz) solid-state laser, with at the same time high power (500 W) and good beam quality (M²<10), used in an extreme-UV source ( at 13,5 nm) for nanolithography. In this kind of lasers, high pumping power leads to thermal effects which lower the performances (efficiency, beam quality) of the laser. It is to say, mainly, an aberrant thermal lensing effect influencing the stability of the resonator. In this work, thermal focal length and spherical aberration are precisely quantified, experimentally and then theoretically. Both studies show a very good match and allow to show the importance of the pumping profile, and of the dependence with temperature of thermal conductivity and dn/dT of the laser crystal in the amplitude of these effects. It is also proven that the position of the laser rod inside the cavity has a significant influence. The consequences of the thermal lens and the spherical aberration are also studied, with simple calculations and simulations with the software Commod Pro. Thanks to these methods, energetic performances of the laser can be predicted with good precision, as well as the M² of the beam, but only in the case of a non aberrating rod. Eventually, thanks to these preliminary studies, compensating devices can be designed, made of phase-plate or a combination of simple lenses and put inside the cavity. Theses devices are very efficient on cavity with a low M², and thanks to them, sources with high brightness can be obtained
Casagrande, Olivier. "Etude théorique et expérimentale de l'architecture d'un laser à solide monocristallin ou céramique dopé ytterbium pour la génération d'impulsions de grande énergie à haute cadence." Phd thesis, Ecole Polytechnique X, 2007. http://pastel.archives-ouvertes.fr/pastel-00002586.
Désécures, Mikaël. "Mise au point de la fluorescence induite par diode laser résolue en temps : application à l'étude du transport des atomes de tungstène pulvérisés en procédé magnétron continu ou pulsé haute puissance." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0137/document.
Magnetron sputter deposition is an established and widely used method for the growth of thin films. Nevertheless, the high level of expectations regarding new applications require a better understanding, controlling, mastering of basic processes governing atoms transport in the view of process optimization. This work consist in the study of transport of sputtered W atoms in direct current and high power impulse magnetron discharges (DC and HiPIMS). A tunable diode laser induced fluorescence technique (TD-LIF) has been developed, in order to measure W sputtered atom velocity distribution function. Measurements were calibrated using laser absorption and were corroborated by deposition rate. In DC, the study of the influence of discharge parameters (power, voltage, Ar/He gas mixture, and distance from target, etc.) highlighted spatial evolution of different regimes of transport: ballistic (energetic atoms), diffusive (thermalized atoms), and mixed (ballistic + diffusive). In HiPIMS, pulsed plasma required to develop a time resolved TD-LIF technique (TR-TDLIF). The additional degree of freedom, given by time dimension allowed for a better understanding of mixed transport which represents the most complicated situation. This technique allowed to measure the kinetic of sputtered W atoms while at the same time providing the possibility to separate characteristic time scales of different processes
Michel, Yann. "Phénomène d'impact à haute vitesse sur cibles minces fragiles : application au projet de laser mégajoule et à la problématique des débris spatiaux." Toulouse 3, 2007. http://www.theses.fr/2007TOU30034.
Due to its optical properties, glass is often essential for optical systems but its inability to undergo large deformations makes it particularly sensitive to high velocity impacts (HVI). The objective of this PhD consist in characterising and modelling damages and matter ejection induced by such impacts on thin monolithic targets (LMJ Disposable Debris Shields, DDS) or multilayered targets (solar cells). An important effort is dedicated to experimental activities including characterisation of fused silica behaviour under shock loadings and of damages induced by 3D HVI (VProj £ 3. 5km/s) on thin brittle targets. SEM and metrological analyses of impacted targets as well as innovating characterisation methods of ejected clouds allowed a better understanding of ejection processes. This phenomenological observation led to improvements of the LS-DYNA Johnson-Holmquist material model (JH-2). This modified model has been coupled with an SPH method and allows to reproduce effects of fragmentation and permanent densification under planar shock loadings. The 2nd part of this work presents the results of 3D modelling activity corresponding to CNES & CEA applications. It has been performed to assess ballistic performances (spallation & perforation), to reproduce damages and matter ejection observed on DDS and solar cells. 3D numerical simulations allowed to identify actual limitations of the code which provides satisfying results for damaging and ejection phenomenology for the range 0-5 km/s. The modelling tool has been used to predict ballistic limits and ejection tendencies due to impact on 2 mm DDS involving various projectiles (shape, material, velocity) in the validated range
Wattellier, Benoit. "Amelioration des performances des chaines lasers solides utilisant l'amplification a derive de frequence : nouveaux reseaux de diffraction a haute tenue au flux et mise en forme programmable de faisceaux lasers par modulation de la phase spatiale." Palaiseau, Ecole polytechnique, 2001. http://www.theses.fr/2001EPXX0027.
Guarguaglini, Marco. "Laser-driven shock compression of liquid mixtures and silica up to extreme thermodynamic conditions of interest for planetary interior models." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLX075/document.
Characterising the behaviour of planetary interiors’ components at extreme conditions (megabar pressures, temperatures of a few thousand Kelvin) is essential to build reliable models describing the evolution and structure of planets. In this thesis, we investigated various components on a wide set of conditions using laser-driven shock compression techniques at the LULI2000 (France) and GEKKO XII (Japan) facilities.Single decaying shocks were employed to study high-pressure / high-temperature states. To reach moderate-temperature conditions, closer to planetary interior profiles, we employed static and dynamic pre-compression techniques coupling Diamond Anvil Cells to shock compression and generating double shocks, respectively.We studied the equation of state of water-ethanol-ammonia mixtures and of pure liquid water and ammonia, of interest for icy giant structure models. Pure ammonia measurements have been particularly challenging due to cell design complexity in reason of its reactivity; we provide the first data obtained with laser shocks, in a pressure domain up to now unexplored. Mixtures data are in agreement with recent ab initio calculations based on the linear mixing approximation.We measured the optical reflectivity of liquid mixtures and silica, a key component of rocky planets’ interiors. From reflectivity data we estimated the electrical conductivity of such components — a crucial parameter for modelling the generation of planetary magnetic fields in the interiors via a dynamo mechanism.Water, ammonia, and water-ethanol-ammonia mixtures exhibit different reflectivity (hence conductivity) behaviours as a function of pressure and temperature. This suggests that pure water should not be used in dynamo models as representative of the icy mixtures.Moreover, we provide the first experimental confirmation of recent ab initio studies showing that the conductivity of silica along isothermal lines is not monotonic at moderate temperatures. Our data provide experimental support for the calculations predicting a dynamo action to occur in super-Earths’ and early Earth’s magma oceans