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Q: Fachverband Quantenoptik und Photonik

Q 4: Nichtlineare optische Effekte und Lichtquellen I

Q 4.7: Talk

Monday, March 19, 2007, 12:00–12:15, 5J

Optimization of high-order harmonics by spatial shaping before the filament — •Jan Lohbreier, Stefan Eyring, Robert Spitzenpfeil, Dominik Walter, Matthias Weger, and Christian Spielmann — University of Würzburg, Department of Physics, Am Hubland, 97074 Würzburg, Germany

The generation of high-order harmonics provides ultrafast and coherent radiation in the EUV regime from a tabletop light source. For many experiments the best achievable control of the EUV photons in terms of brightness and spectrum is necessary.

We present a way of optimizing the output of the high-order harmonic generation process by means of spatial shaping. This phase shaping is performed with a PPM-SLM with a resolution of 768x768 pixels and employing a genetic algorithm. After spatially shaping the beam profile the laser is generating a filament in a gas-filled tube. The spectrally-broadened pulses are then compressed to about 12fs using a prism-compressor and used for harmonic generation in a gas-jet. Our results show that an optimization can be achieved regarding the overall photon flux. Further improvements (harmonic beam profile, selectivity of the spectrum) still need to be investigated.