Letteratura scientifica selezionata sul tema "Impulsions laser nanosecondes"
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Articoli di riviste sul tema "Impulsions laser nanosecondes":
Utéza, O., M. Boyomo-Onana, Ph Delaporte, N. Destouches, B. Fontaine, M. Sabonnadière e M. L. Sentis. "Modélisation de l'amplification d'une impulsion laser UV nanoseconde dans un milieu à excimères". Le Journal de Physique IV 11, PR7 (ottobre 2001): Pr7–51—Pr7–52. http://dx.doi.org/10.1051/jp4:2001718.
Tesi sul tema "Impulsions laser nanosecondes":
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.