A laser source for the generation of intense attosecond pulses and its first applications
The continuous development and improvement of laser sources has steadily increased\nthe number of applications and pushed the limit of high precision measurements\nin various fields. The goal of the work presented in this thesis is to improve the\nspectrally broadened Ti:sapphire laser system used for isolated extreme ultraviolet\n(XUV) pulse generation, which has, in the last decade, allowed the study of electron\ndynamics on a sub-femtosecond (1 fs = 10^-15 s) level and delivered new insights into\nultrafast dynamics of electrons in atoms, molecules and solids.\nBy adding a second stage amplifier to the commonly used one-stage chirped pulse\namplification laser system the compressed output power of a sub-5 fs laser system\nhas been tripled to 1.5 mJ. A crucial part for achieving this result is the comparison\nof two different efficient compressor setups in order to optimize the compression.\nWith these higher pulse energies, it is possible to increase the generated photon \nux\nin an isolated attosecond (10^-18 s) pulse and to push the XUV photon energy higher.\nRun at 4 kHz repetition rate, integrative measurements with sub-2 cycle laser pulses\ncan be conducted much faster than with most laser sources in this energy range.\nThe resulting pulses are used for high-harmonic generation (HHG) and characterized\nvia attosecond streaking, demonstrating excellent stability and quality of the\nwhole laser system.\nFirst experiments with these pulses were conducted by probing the temporal behavior\nof the photo-emission of the giant resonance of 4d electrons in xenon with broadband\nXUV-pulses at 100 eV and inducing and measuring the nonlinear propagation\nin fused silica at high intensities via its effect on the waveform of the ultra-short\nvisible-near-infrared pulse measured by means of attosecond streaking.\nThe higher pulse energy of the driving laser field will also prove to be very useful as\nsoon as nonlinear effects besides HHG contribute to the pump and probe setup e.g.\nan ultrashort UV-pulse is used to pump electron dynamics which are subsequently\nprobed with high temporal resolution by the XUV-pulse.