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 7 of 7 for “"Coherent Phonons"”.
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Ultrafast lattice dynamics in photoexcited nanostructures : femtosecond X-ray diffraction with optimized evaluation schemes
… namely the excitation and propagation of coherent phonons, in photoexcited thin films and superlattice structures of the metallic perovskite SrRuO3. Due to the quasi-instantaneous coupling of the lattice to the optically excited electrons in this material a spatially and temporally …
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Hypersound interaction studied by time-resolved inelastic light and x-ray scattering
… about the generation, detection and coupling of coherent gigahertz longitudinal acoustic phonons, also called hypersonic waves. To generate such high frequency phonons, femtosecond near infrared laser pulses were used to heat nanostructures composed of perovskite oxides on an ultrashort …
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Electronic excitation and atomic forces in optically excited group V semimetals
… collective atomic motion, referred to as coherent phonon motion. The recent development of ultrafast optical spectroscopy has greatly advanced our understanding of these phenomena. However, many aspects of ultrafast phenomena are still poorly understood. For instance, experiments on a …
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Probing Coherent States and Nonlinear Properties in Multifunctional Material Systems
… of the fundamental understanding of their coherent states and nonlinear optical properties. This study is aimed at characterizing, modeling, and controlling the fundamental electronic, phononic, and spin properties of several classes of materials through nonequilibrium and nonlinear …
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To Couple or not to Couple? Exploring Vibronic Coupling in Organic Semiconductors
… systems, disordered hosts typically lack coherent lattice dynamics. However, the chapter 4 titled “Short-Range Exciton–Phonon Coupling in Disordered Molecular Solids” shows that even in amorphous hosts like CBP, low-frequency coherent phonons can emerge and couple to excitons in radical …
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Ultrafast dynamics in quantum materials probed by time-and-momentum-resolved techniques
… the second part of the thesis focuses on the coherent acoustic phonons in quantum materials observed with UED. The crystalline lattice is the building block of any solid-state system and, thus, the most important aspect in condensed matter physics research. The study of coherent acoustic …
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Spectroscopic perspectives on ultrafast coupling phenomena in perovskite oxides
… spectroscopy. I focus on the observation of coherent phonon propagation by time resolved Brillouin scattering: following the excition of metal transducer films with a femtosecond infrared pump pulse, coherent phonon dynamics in the GHz frequency range are triggered. Their propagation is …