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Q: Fachverband Quantenoptik und Photonik
Q 26: Poster Ultrakurze Laserpulse
Q 26.10: Poster
Dienstag, 11. März 2008, 16:30–19:00, Poster C1
Spatial characterization and wavefront measurements of high-order harmonics — •Stefan Eyring1, Christian Kern1, Jan Lohbreier1, Robert Spitzenpfeil1, Matthias Weger2, and Christian Spielmann1 — 1Universität Würzburg, Physikalisches Institut, Am Hubland, Würzburg, Deutschland — 2ETH Zürich, Institut für Quantenelektronik, Zürich, Schweiz
High-order harmonic radiation provides coherent light up to the soft x-ray regime. Because of the fundamentally low photon yield one needs to focus the generated radiation. The focussing of the beam of harmonics depends strongly on its wavefront. Therefore detailed information on the beam profile and wavefront are necessary.
We present experimental measurements with a Hartmann-type wavefront sensor suited for use in the EUV region. For analysing the data Zernicke polynomials are used and quantitative physical interpretation is therefore possible. In addition we present measurements with a knife-edge scan to determine the beam parameter M2 which is a wavelength-independent measure of beam quality. This scheme allows us to calculate different beam parameters of the beam of high-order harmonics.
Using the information gained through this setup we utilise an adaptive spatial pulse shaping technique. Changing the wavefront of the incident driving laser beam of the generating process makes it possible to increase the high-order harmonic yield at the detector.