Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 31 for “"laser field"”.
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Investigation of Closed-Loop Control of Polyatomic Molecules
… of DMMP and CH2BrI in strong femtosecond laser fields, coherent control using closed-loop optimization method for bond dissociation in both DMMP and CH2BrI, as well as application of closed-loop control as a detection method for air borne organophosphates such as DMMP. Investigation of …
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High harmonic generation by short laser pulses: time-frequency behavior and applications to attophysics
… in which noble gas atoms excited by an intense laser field at frequency ω<sub>1</sub> emit radiation of higher frequencies that are odd integer multiples of ω<sub>1</sub>. Driven by an infrared laser, high harmonic radiation can span from the optical into the extreme ultraviolet (XUV) frequency …
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Attosecond Wave Packet Metrology
… interaction of atoms with ultrashort, intense laser pulses whose electric field approaches the strength of inner-atomic electric fields. This thesis presents experiments around the generation, characterization and application of attosecond pulses. First, we study the influence of the atomic …
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Simulations of laser-induced correlated many-electron dynamics in molecular systems
In this thesis, simulations of laser-driven many-electron dynamics in molecules are presented, i.e., the interaction between molecules and an electromagnetic field is demonstrated. When a laser field is applied to a molecular system, a population of higher electronic states takes place as well as …
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Homodyne High-harmonic Spectroscopy: Coherent Imaging of a Unimolecular Chemical Reaction
… and collision physics entwined by a strong laser field. An electron, initially tunnel-ionized by the field, driven away then back in the continuum, finally recombines back to rest in its initial ground state via a radiative transition. The emitted attosecond (atto=10^-18) XUV light pulse …
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Einfluss dynamischer Resonanzen auf die Wechselwirkung optischer Femtosekunden-Pulse mit transparenten Dielektrika
… dielectric polarization follows the electric field instantaneously, if the fundamental wavelength is far away from any resonance. However, with increasing intensity - in the regime of nonlinear optics - unexpected resonances may occur through the generation of higher harmonics or by the ac …
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Strong Optical Field Ionization of Solids
… to conduction band in the presence of an intense laser field is explored theoretically in semiconductors and dielectrics. Experiments on intense laser driven dielectrics have revealed population transfer to the conduction band that differs from that seen in semiconductors. Our research explores …
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A simple model of above threshold ionization
… in this work. It is based on modeling the pulsed laser beam involved in ionization as a cylinder consisting of elementary cells whose volumes are very small compared to the pulse volume. A cell is occupied by a number of photons determined probabilistically and found to follow the Poisson …
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Fundamental Studies And Applications Of Strong Field Ionization
<p>In an intense laser field, atoms and molecules experience tunneling ionization directly to the continuum. We used this method to study several aspects and applications of strong field ionization (SFI) in atoms and molecules. One study used SFI to probe the photofragments produced by …
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Laser-driven electron acceleration in infinite vacuum
I first review basic models for laser-plasma interaction that explain electron acceleration and beam confinement in plasma. Next, I discuss ponderomotive electron acceleration in infinite vacuum, showing that the transverse scattering angle of the accelerated electron may be kept small with a …
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Theory Advances in High-Precision Two-Photon Spectroscopy
… relativistic, radiative and non-dipole laser-field effects. An important broadening effect of the experimentally observed spectra in the hydrogen 1S–2S spectroscopy experiment at the Max–Planck–Institut für Quantenoptik (MPQ) is identified and quantitatively described, as well as …
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Cooperative Optical Non-linearity in a blockaded Rydberg Ensemble
… to tune the interactions with an external field is also verified. This cooperative effect can be used to manipulate light at the single photon level, which is relevant for applications in quantum information processing. A theoretical model is developed to show that the non-linearity can be …
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Radiation pressure effects in a suspended Fabry-Perot cavity
… coupling is presented, whereby a strong coherent laser field interacts with a classical harmonic oscillator. We show that such a system is well described using standard techniques from control theory. We measure the properties of an optical spring, whereby the optical field increases the rigidity …
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Electronic properties of bilayer graphene in a steady magnetic field
… bilayer graphene in a steady, parallel magnetic field. Using the tight–binding model, and taking into account relevant tight–binding parameters, we find a new contribution to the electronic Hamiltonian describing the orbital effect of the magnetic field. We consider the effect of the magnetic …
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Discrete Variable Representation Of The Angular Variables In Quantum Three-Body Scattering
… presence of a non-central interaction such as a laser field, where the total angular momentum is not conserved during the collision process. The Discrete Variable Representation is a new method for solving the quantum-mechanical three-body scattering problem to obtain the total cross section. The …
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Quantum dynamics in laser–assisted collisions, laser–molecule interactions, and particle–surface scattering
… applied to ion – atom collisions in a strong laser field, the vibrational nuclear motion in small homonuclear diatomic molecular ions, and for the scattering of an ion in front of a metallic surface. For laser-assisted proton – hydrogen collisions it is shown, that strong circularly polarized …
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Stabilization of autoionizing states
… in Barium was examined for the case when a laser field was used to induce stimulated emission of the excited core electron. Stabilization is referred to all the atoms that form a singly excited neutral state after being in a doubly excited autoionizing state. Relative to pure fluorescence, …
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Exotic Species of Hydrogen
… processes of the negative Hydrogen ion in strong laser-field regimes. A Keldysh-Faisal-Reiss theory allows semiclassical interpretations of complex ionization mechanisms in strong laser-fields due to its conformity with the Feynman path integral formalism. We employ a new kind of photoelectron …
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Laser-Driven Particle Acceleration - Improving Performance Through Smart Target Design
Laser-driven particle acceleration makes use of sub-picosecond, pulsed, high-power laser systems, capable of producing intensities ~10^{19} W/cm^2 at the laser focus to form plasmas, and use ultra-relativistic and nonlinear dynamics to produce quasistatic acceleration fields. This allows electrons …
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Three-Dimensional Fluorescence Microscopy by Optical Scanning Holography
… is scanned with an optically heterodyned laser field consisting of a Fresnel zone pattern. A unique acousto-optic modulator configuration is employed to generate a suitable heterodyne frequency for excitation of the fluorescent object. The optical response of a solution containing a high …
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