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Q: Quantenoptik
Q 8: Generation of Short Pulses II
Q 8.3: Talk
Monday, April 2, 2001, 18:00–18:15, H 2013
Optimizations of high order harmonic generation in hollow core fiber for different laser systems — •P. Zhou1, O. Heinz1, J. Beesley1, A. Fedotov2, A. Naumov2, A. Zheltikov2, and D. von der Linde1 — 1Institut für Laser- und Plasmaphysik, Universität Essen, 45117Essen — 2International Laser Center, Faculty of Physics, Moscow State University, 119899 Moscow, Russia
The use of hollow core fiber as target for high order harmonic generation has the advantage of possibility to build simple system for harmonic generation with low gas consumption compare to gas jet. The waveguide dispersion of the fiber makes it possible to reach the phase matching condition and therefore to enhance the efficiency of the harmonic generation drastically. Due to the absorption of harmonic energie and the ionization the phase matching is not only affected by gas pressure but also by the length of the fiber, laser intensity and pulse duration. We studied both in experiment and theory the enhancement of the harmonic intensity as function of different parameters.
In experiment we generated the harmonic with different lengths of fiber, laser intensities and pulse duration as function of gas pressure. The change of the pulse duration was done by using different laser systems with a pulse duration of 40 and 80 fs. The results show, that the enhancements of the efficiency have complete different dependence for different pulse duration. For both systems we could find their individuell optimal conditions and got comparable efficiencies. We discuss the experimental results and compare them with the theory based on a model including the absorption, ionization in hollow core fiber.