ISBN 9783843902762

978-3-8439-0276-2, Reihe Physik

Manuel Mittenzwey
High Harmonic Generation for the XUV seeding experiment at FLASH

139 Seiten, Dissertation Universität Hamburg (2011), Hardcover, A5

Zusammenfassung / Abstract

The Free electron LASer in Hamburg (FLASH), operating in the Self-Amplified Sponta- neous Emission (SASE) mode, is currently the most intense femtosecond light source in the eXtreme-UltraViolet (XUV) regime. However, the statistical nature of SASE leads to intensity fluctuations of the Free Electron Laser (FEL) pulses. Moreover, the elec- tron acceleration process introduces arrival-time fluctuations of the electron bunch at the undulator entrance, which leads to a temporal jitter with respect to the synchroniza- tion system. This jitter limits the resolution of corresponding pump-probe experiments. In order to reduce these pulse-to-pulse fluctuations, a seeding section for the electron bunch has been installed in 2009/2010. Here, XUV seed pulses from a High-Harmonic Generation (HHG) source are overlapped in space and time with the electron bunches in new variable-gap undulators installed upstream the existing SASE undulator. Behind the undulator section, the seeded FEL radiation will be deflected by a mirror into an experimental container for beam characterization. A fraction of the optical laser, used as the driving laser for HHG, is also transported into the experimental container, thus, tem- poral diagnostics like cross-correlations between the synchronized seeded FEL and optical pulses are possible. Emphasis of this work is the construction and characterization of the HHG source.