Nonlinear terahertz spectroscopy in one and two dimensions [Elektronische Ressource] / Wilhelm Kühn. Gutachter: Elsässer ; Hamm ; Masselink

Nonlinear Terahertz Spectroscopyin One and Two DimensionsDISSERTATIONzur Erlangung des akademischen GradesDr. rerum naturalium(Dr. rer. nat.)im Fach Physikeingereicht an derMathematisch-Naturwissenschaftlichen Fakultät IHumboldt-Universität zu BerlinvonDipl.-Phys. Wilhelm Kühn20. Oktober 1980 in HattingenPräsident der Humboldt-Universität zu Berlin:Prof. Dr. Jan-Hendrik OlbertzDekan der Mathematisch-Naturwissenschaftlichen Fakultät I:Prof. Dr. Andreas HerrmannGutachter:1. Prof. Dr. Elsässer2. Prof. Dr. Hamm3. Prof. Dr. Masselinkeingereicht am: 09. Dezember 2010Tag der mündlichen Prüfung: 10. Februar 2011AbstractThe presented thesis concerns fundamentals and applications of nonlinear terahertz(THz) spectroscopy. Two widely used sources for THz radiation, the quantum cascadelaser (QCL) and a laser-induced plasma, are investigated by means of THz spectroscopy.This thesis demonstrates for the first time a gain recovery time of several hundred fem-toseconds within a QCL. Furthermore, we explored the exact generation process of THzpulses within a laser-induced two-color plasma. A comparison with theoretical predictionsidentifies unambiguously the ionisation current as origin of the emitted THz radiation. Be-sides, the influence of propagation effects within the plasma is experimentally examinedand theoretically explained.