Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 79: Poster: Ultrafast Electron and Spin Dynamics at Interfaces

O 79.7: Poster

Mittwoch, 14. März 2018, 18:15–20:30, Poster A

Development of a tabletop femtosecond broadband soft X-ray source — •Oscar Naranjo-Montoya, Manuel Bridger, Alexander Tarasevitch, and Uwe Bovensiepen — Universität Duisburg-Essen, Fakultät für Physik, 47057 Duisburg, Germany

Pump-probe experiments with optical excitation and absorption spectroscopy in the soft X-ray range on a femtosecond timescale are useful to analyze electronic and magnetic properties of complex material systems and their temporal evolution. These experiments have become available at Free Electron Laser and Synchrotron sources. However, due to the limited accessibility of these large scale facilities, systematic studies remain arduous to perform. Therefore, it will be useful to develop compact laboratory based sources. A promising approach is to use high harmonic generation in noble gases driven by mid-infrared femtosecond pulses. It has already been shown that with such radiation it is possible to generate photon energies that reach the keV regime [1]. We present the development of a high power two stage Optical Parametric Chirped-Pulse Amplifier as a pump for a tabletop soft X-ray source dedicated to absorption spectroscopy. 1 ps pump pulses at 515 nm amplify seed pulses at 800 nm by a factor of 20000. Their wavelength is converted to 1500 nm with a bandwidth of 40 nm and energy of 10 mJ. The 1500 nm pulses are the seed to produce λ=3200 nm with 100 fs duration. The achieved spatial, spectral and temporal pulse characteristics and an estimate of the soft X-ray flux will be presented. This work is funded by the DFG through SFB 1242, TP A05. [1] T. Popmintchev et al., Science 336, 1287-1291 (2012).