Teses / dissertações sobre o tema "Relativistic Optics"
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Kjellsson, Lindblom Tor. "Relativistic light-matter interaction". Doctoral thesis, Stockholms universitet, Fysikum, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-147749.
Texto completo da fonteShen, Xiaozhe. "Optics measurement and correction for the Relativistic Heavy Ion Collider". Thesis, Indiana University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3636204.
Texto completo da fonteThe quality of beam optics is of great importance for the performance of a high energy accelerator like the Relativistic Heavy Ion Collider (RHIC). The turn-by-turn (TBT) beam position monitor (BPM) data can be used to derive beam optics. However, the accuracy of the derived beam optics is often limited by the performance and imperfections of instruments as well as measurement methods and conditions. Therefore, a robust and model-independent data analysis method is highly desired to extract noise-free information from TBT BPM data. As a robust signal-processing technique, an independent component analysis (ICA) algorithm called second order blind identification (SOBI) has been proven to be particularly efficient in extracting physical beam signals from TBT BPM data even in the presence of instrument's noise and error. We applied the SOBI ICA algorithm to RHIC during the 2013 polarized proton operation to extract accurate linear optics from TBT BPM data of AC dipole driven coherent beam oscillation. From the same data, a first systematic estimation of RHIC BPM noise performance was also obtained by the SOBI ICA algorithm, and showed a good agreement with the RHIC BPM configurations. Based on the accurate linear optics measurement, a beta-beat response matrix correction method and a scheme of using horizontal closed orbit bumps at sextupoles for arc beta-beat correction were successfully applied to reach a record-low beam optics error at RHIC. This thesis presents principles of the SOBI ICA algorithm and theory as well as experimental results of optics measurement and correction at RHIC.
Mondal, Ritwik. "Relativistic theory of laser-induced magnetization dynamics". Doctoral thesis, Uppsala universitet, Materialteori, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-315247.
Texto completo da fonteKemp, Gregory Elijah. "Specular Reflectivity and Hot-Electron Generation in High-Contrast Relativistic Laser-Plasma Interactions". The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1375386740.
Texto completo da fonteCanova, Lorenzo. "Generation and shaping of ultra-short, ultra-high contrast pulses for high repetition rate relativistic optics". Phd thesis, Ecole Polytechnique X, 2009. http://pastel.archives-ouvertes.fr/pastel-00005764.
Texto completo da fonteHakl, Michael. "Infrared magneto-spectroscopy of relativistic-like electrons in three-dimensional solids". Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAY085/document.
Texto completo da fonteThe use of the Dirac/Weyl equation leads to a conceptual simplification in a description of the band structure in solids at low energy scales. In particular, electron-hole excitations can be regarded as an analogue to the relativistic case with several expected phenomena to be observed in the condensed systems such as a suppressed back-scattering, linear optical conductivity or the manifestation of the Fermi arcs and particle's chirality. Moreover, the semimetallic phase also symbolizes a boundary between the trivial and topological insulators and thus play a crucial role for the material classification. The size of the gap qualitatively affects the type of the energy dispersion by a continuous crossover from the linear to parabolic bands. This fact can be easily understood as a classical or ultra-relativistic limit of the motion of a free massive particle.Infrared Fourier transform spectroscopy is a unique technique for studying optical excitations in a wide range of energies and it represents in combination with the high magnetic field a powerful tool for probing electronic structure and overcomes the main obstacle of the gapless systems that is a strong doping due to the structural disorder.The first part of the work is devoted to cadmium arsenide, where we elaborate an approach to qualitatively distinguish between the Dirac and Kane systems that was used to prove on the basis of the observed magneto-optical response the realization of the nearly gapless Kane model with a striking similarity to HgCdTe, contradicting the existence of purely Dirac cones. The magneto-reflectivity revealed a strong splitting of the plasma edge that turns into the cyclotron resonance characteristic by a squareroot-of-B dependence in the high magnetic field with a particular behaviour in the quantum limit independent on the initial Fermi level. In contrast, the magneto-transmission revealed interband Landau level transitions that could be only interpreted as a flat-to-cone type in order to preserve a full consistency of the model. The Dirac cones predicted by theory are feasible to coexist within the Kane model in the form of a substructure described by the Bodnar model that approximates the complex crystal structure by a simple antifluorite cell, which allows to use the conventional k.p-theory.In the second part, we focus on bismuth selenide entitled as an archetypal 3D topological insulator. We study a peculiar condition fulfilled for the BHZ-hamiltonian that brings intriguing properties such as an unusual relation of the spin gap and cyclotron resonance, the specific pinning between fancharts of Landau subsets or the compensated g-factors of the conduction and valence bands. The photoluminescence measurements showed a direct-gap emission, that gives a new insight to the widely accepted structure from ARPES data, where the declared camel-back structure of the valence band needs to be explained within the surface confinement and the Dirac point of the surface state should be repositioned with respect to the bulk bands. The magneto-optical response can be fully explained in a classical picture of the Pauli paramagnetism as a purely occupational effect. Such behaviour is evinced in the transmission as a gradual splitting of the interband absorption edge with a successive saturation due to the partial or total spin polarization of electrons. The related dichroism drives also a strong linear Faraday rotation described by a simple model of the Verdet constant that depends only on the Fermi level
Böhle, Frederik. "Near-single-cycle laser for driving relativistic plasma mirrors at kHz repetition rate - development and application". Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLX116/document.
Texto completo da fonteVery short light pulses allow us to resolve ultrafast processes in molecules, atoms and condensed matter. This started with the advent of Femtochemistry, for which Ahmed Zewail received the Novel Prize in Chemistry in 1999. Ever since, researcher have been trying to push the temporal resolution further and we have now reached attosecond pulse durations. Their generation, however, remains very challenging and various different generation mechanisms are the topic of heated research around the world.Our group focuses on attosecond pulse generation and ultrashort electron bunch acceleration on solid targets. In particular, this thesis deals with the upgrade of a high intensity, high contrast, kHz, femtosecond laser chain to reach the relativistic interaction regime on solid targets. Few cycle driving laser pulses should allow the generation of intense isolated attosecond pulses. A requirement to perform true attosecond pump-probe exeriments.To achive this, a HCF postcompression scheme has been conceived and implemented to shorten the duration of a traditional laser amplifier. With this a peak intensity of 1TW was achieved with near-single-cycle pulse duration. For controlled experiments, a vacuum beamline was developed and implemented to accurately control the laser and plasma conditions on target.During the second part of this thesis, this laser chain was put in action to drive relativistic harmonic generation on solid targets. It was the first time ever that this has been achieved at 1 kHz. By CEP gating the few-cycle-pulses, single attosecond pulses were generated. This conclusion has been supported by numerical simulations. Additionally a new regime to accelerate electron bunches on soft gradients has been detected
Cunningham, Eric Flint. "Photoemission by Large Electron Wave Packets Emitted Out the Side of a Relativistic Laser Focus". BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/3054.
Texto completo da fonteGustas, Dominykas. "High-repetition-rate relativistic electron acceleration in plasma wakefields driven by few-cycle laser pulses". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLX118/document.
Texto completo da fonteContinuing progress in laser technology has enabled dramatic advances in laser wakefield acceleration (LWFA), a technique that permits driving particles by electric fields three orders of magnitude higher than in conventional radio-frequency accelerators. Due to significantly reduced space charge and velocity dispersion effects, the resultant relativistic electron bunches have also been identified as a candidate tool to achieve unprecedented sub-10 fs temporal resolution in ultrafast electron diffraction (UED) experiments. High repetition rate operation is desirable to improve data collection statistics and thus washout shot-to-shot charge fluctuations inherent to plasma accelerators. It is well known that high-quality electron beams can be achieved in the blowout, or "bubble" regime, which is at present regularly accessed with ≈ 30 fs Joule-class lasers that can perform up to few shots per second. Our group on the contraryutilized a cutting edge laser system producing few-mJ pulses compressed nearly to a single optical cycle (3.4 fs) to demonstrate for the first time an MeV-grade particle accelerator with properties characteristic to the blowout regime operating at 1 kHz repetition rate. We further investigate the plasma density profile and exact laser pulse waveform effects on the source output, and show that using special gas microjets a charge of tens of pC/shot can be achieved. We expect this technique to lead to a generation of highly accessible and robust instruments for the scientific community to conduct UED experiments or to be used for other applications. This work also serves to expand our knowledge on the scalability of laser-plasma acceleration
Kaur, Jaismeen. "Development of an intense attosecond source based on relativistic plasma mirrors at high repetition rate". Electronic Thesis or Diss., Institut polytechnique de Paris, 2024. http://www.theses.fr/2024IPPAE007.
Texto completo da fonteThe experimental work presented in this manuscript was carried out at Laboratoire d’Optique Appliquée (LOA, Palaiseau, France) on a compact kHz multi-mJ energy laser system capable of delivering waveform-controlled near-single-cycle pulses. The first part of this work is focused on improving the performance of this laser source by integrating a cryogenically-cooled multi-pass amplifier in the laser chain in order to increase the output energy, enhance the laser waveform stability, making the laser source more stable and reliable, and with more overall reproducible day-to-day performance. Furthermore, we explore laser post-compression and temporal contrast enhancement in a multipass cell. In the future, this post-compression scheme when power-scaled and integrated into the laser chain will further enhance the focused pulse intensity for experiments.The second part of this work focuses on using the laser system to drive relativistic plasma mirrors on the surface of initially-solid targets to generate highly energetic particle beams (ions and electrons) and harmonic radiation in the extreme ultraviolet region, corresponding to attosecond pulses (1 as = 10-18 s) in the time domain. We could produce relativistic electron beams by localized injection of electrons into the nonlinearly reflected laser field by the plasma mirror. Additionally, we could generate nearly-collimated MeV-class proton beams in a controlled pump-probe experiment. By stabilizing the waveform of the driving laser pulses, we could temporally gate the interaction process on the target surface and produce isolated attosecond pulses. We performed a comprehensive parameter study to fully characterize and optimize the spatio-spectral properties of the emitted XUV attosecond pulses, laying the groundwork for their refocusing for applications
Janeiro, Fernando M. "Quiralidade e Não-Linearidade em Fibras Ópticas". Doctoral thesis, IST, 2004. http://hdl.handle.net/10174/2008.
Texto completo da fonteHenriksson, Johan. "Molecular Quadratic Response Properties with Inclusion of Relativity". Doctoral thesis, Linköping : Department of Physics, Chemistry and Biology, Linköping University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11035.
Texto completo da fonteScott, Jeremy Stephen. "ELASTIC SCATTERING AT RELATIVISTIC ENERGIES OF ALPHA PARTICLES AND PIONS BY NUCLEI USING AN OPTICAL POTENTIAL". OpenSIUC, 2012. https://opensiuc.lib.siu.edu/dissertations/500.
Texto completo da fonteOuillé, Marie. "Génération d'impulsions laser proches du cycle optique en durée pour l'interaction laser-matière relativiste à haute cadence". Electronic Thesis or Diss., Institut polytechnique de Paris, 2022. http://www.theses.fr/2022IPPAE007.
Texto completo da fonteThis experimental thesis was essentially conducted at Laboratoire d’Optique Appliquée in Palaiseau (France), on a laser system capable of delivering near-single-cycle duration pulses containing a few mJ of energy at 1kHz repetition rate: the Salle Noire 2. This laser is a Titanium:Sapphire double CPA system with a nonlinear filter in between (based on the crossed polarized wave generation effect) for temporal contrast enhancement, followed by a stretched-flexible hollow-core-fiber based post-compression stage. Using this system, we study laser-matter interaction in the relativistic regime at high repetition rate. We can, on one hand, in gas jets, accelerate electrons in the wakefield of the laser up to several MeVs; and on the other hand, by interacting with plasma mirrors, generate high order harmonics which are associated to bright attosecond pulses in the time domain. Despite the technological prowess in these experiments, the properties of the XUV and electron beams thus generated remain scarcely compatible with the main applications downstream. Following up on previous works in Salle Noire 2, the objective of this thesis was to obtain beams with stable properties, which was achieved by making the laser system more stable and reliable, as well as implementing a fast carrier-envelope phase control loop. By varying the carrier-envelope phase of the laser pulses, we could generate XUV continua/isolated attosecond pulses by forming a relativistic-intensity temporal gate at the surface of the plasma mirror, and also produce electron beams exhibiting stable energy and angle of emission, by controlling the electron injection within the plasma accelerator. Additionally, different regimes of interaction with plasma mirrors were experimentally investigated, such as wakefield acceleration of electrons in long plasma density gradients, and the acceleration of protons on the target’s front side (onto which the laser impinges) along the target no rmal direction, in order to measure new observables (electron energy spectra, proton beam divergence) and thus gain deeper insights into the laser-plasma dynamics
Oubrerie, Kosta. "Amélioration de l'efficacité des accélérateurs laser-plasma". Electronic Thesis or Diss., Institut polytechnique de Paris, 2022. http://www.theses.fr/2022IPPAE002.
Texto completo da fonteTo generate high energy electron beams, conventional accelerators use radio frequency waves to accelerate charged particles to relativistic speeds. However, the accelerating electric field produced is limited to a few tens of megavolts per metre, mainly due to a breakdown phenomenon. Very large facilities are therefore needed to reach sufficiently high energies. For example, the Stanford Linear Accelerator (SLAC), which is the world's longest linear accelerator, accelerates electrons up to 50 GeV over a distance of 3.2 km. Laser-Plasma Accelerators can produce electric fields exceeding 100 GV/m, that are about three orders of magnitude larger than those obtained by radiofrequency-cavity accelerators. They could thus allow for a drastic decrease of the size of accelerators for scientific, medical and industrial applications. Yet, several bottlenecks have to be solved before these applications can be really implemented. It is notably necessary to demonstrate the efficient production of high-quality, multi-GeV electron beams at a high-repetition rate.The doctoral project tackles this problem by exploring new methods for increasing the energy of the electron beams thanks to techniques that are compatibles with arbitrarily high laser powers and repetition rates and that can be combined with controlled injection methods. Indeed, high energy or controlled injection electron beams have been obtained separately during the last fifteen years, but never combined. This thesis presents the work carried out on the guiding techniques as well as on the electron injection techniques which allowed to obtain experimentally good quality beams at high energies. This work was done in particular through the optimisation of a new optic designed at the Laboratoire d'Optique Appliquée, the axiparabola, as well as the development of gas jets specific to laser-plasma acceleration
Ricci, A. "Développement d'une source laser ultra-brève, stabilisée en phase et à haut contraste, pour l'optique relativiste haute cadence". Phd thesis, Ecole Polytechnique X, 2013. http://pastel.archives-ouvertes.fr/pastel-00841459.
Texto completo da fonteHinschberger, Yannick. "Etude théorique des effets relativistes induits par une impulsion lumineuse ultra-rapide dans la matière". Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00923154.
Texto completo da fonteШовкопляс, Оксана Анатоліївна, Оксана Анатольевна Шовкопляс, Oksana Anatoliivna Shovkoplias e А. С. Мазманишвили. "Формирование оптических изображений потока фотонов, испускаемых пучками релятивистских электронов". Thesis, Сумский государственный университет, 2014. http://essuir.sumdu.edu.ua/handle/123456789/39430.
Texto completo da fonteChandra, Nitin. "Topics In Noncommutative Gauge Theories And Deformed Relativistic Theories". Thesis, 2012. https://etd.iisc.ac.in/handle/2005/2468.
Texto completo da fonteChandra, Nitin. "Topics In Noncommutative Gauge Theories And Deformed Relativistic Theories". Thesis, 2012. http://etd.iisc.ernet.in/handle/2005/2468.
Texto completo da fonteSchumaker, Bonny Laura. "Theoretical Investigations in Nonlinear Quantum Optics, Theory of Measurement, and Pulsations of General Relativistic Models of Neutron Stars". Thesis, 1985. https://thesis.library.caltech.edu/10414/8/Schumaker_BL_1985.pdf.
Texto completo da fonteThis thesis is a collection of six papers. The first four constitute the heart of the thesis; they are concerned with quantum mechanical properties of certain harmonic-oscillator states. The first paper is a discourse on single-mode and two-mode Gaussian pure states (GPS), states produced when harmonic oscillators in their ground states are exposed to potentials that are linear or quadratic in oscillator position and moment um variables (creation and annihilation operators). The second and third papers develop a formalism for analyzing two-photon devices (e.g., parametric amplifiers and phase-conjugate mirrors), in which photons in the ouput modes arise from two-photon transitions, i.e., are created or destroyed two at a time. The states produced by such devices are single-mode and two-mode "squeezed states", special kinds of GPS whose low-noise properties make them attractive for applications in such fields as optical communications and gravitational wave detection. The fourth paper is an analysis of the noise in homodyne detection, a phase-sensitive detection scheme in which the special properties of (single-mode) squeezed states are revealed as an improved signal-to-noise ratio relative to that obtained with coherent states (the states produced, e.g., by a laser).
The fifth and sixth papers deal with problems of a different nature from that of the previous papers. The fifth paper considers the validity of the "standard quantum limit" (SQL) for measurements which monitor the position of a free mass. It shows specifically that when the pre-measurement wave functions of the free mass and the measuring apparatus(es) are Gaussian (in the general sense, which includes so-called "contractive states"), measurements described by linear couplings to the position or to both the position and momentum are limited by the SQL. The sixth paper develops the mathematical theory of torsional (toroidal) oscillations in fully general relativistic, nonrotating, spherical stellar models, and of the gravitational waves they emit.
Bezděková, Barbora. "Elektromagnetické vlny v disperzních a refraktivních relativistických systémech". Master's thesis, 2019. http://www.nusl.cz/ntk/nusl-405008.
Texto completo da fonteNádvorník, Lukáš. "Relativistické spintronické efekty v polovodičových strukturách". Doctoral thesis, 2016. http://www.nusl.cz/ntk/nusl-352058.
Texto completo da fonte"Effect of Chaos and ComplexWave Pattern Formation in Multiple Physical Systems: Relativistic Quantum Tunneling, Optical Meta-materials, and Co-evolutionary Game Theory". Doctoral diss., 2012. http://hdl.handle.net/2286/R.I.15796.
Texto completo da fonteDissertation/Thesis
Ph.D. Electrical Engineering 2012
Oliveira, Micael José Tourdot de. "Relativistic effects in the optical response of low-dimensional structures : new developments and applications within a time-dependent density functional theory framework". Doctoral thesis, 2009. http://hdl.handle.net/10316/9621.
Texto completo da fonteThe characterization of the electronic response of nanostructures to external electromagnetic fields is of great importance, both from the theoretical and technological points of view. In contrast to light elements, new physical processes and phenomena appear in heavy elements, where relativistic effects, like spin-orbit coupling cannot be ignored. In this work we develop the theoretical framework and the numerical tools needed to address those processes within time-dependent density functional theory (TDDFT). We first apply this methodology to the study of the photoabsorption cross-section of small cationic xenon clusters. Overall, we find our results to be in good agreement with experiment, except for the incorrect prediction of the relative intensities of the peaks. As a second application, we investigate the effect of spin-orbit coupling in the optical response of small gold clusters. We find that this effect is always noticeable, but its importance depends on the dimensionalities of the clusters (the effect is larger for wires than for 2D and 3D structures) and on the size of the clusters (the effect is “quenched” with increasing cluster size). Finally, we study the role of spin noncollinearity in the excited state properties of small chromium and iron clusters and its interplay with spin-orbit coupling. In particular, we compare the dipole and spin-dipole responses of clusters with collinear and noncollinear spin arrangements. We find that, in all cases, the different electronic structure of collinear and noncollinear configurations are reflected to some extent in the spectra. On the contrary, no direct evidence of spin-orbit coupling can be found in the spectra.