Regensburg 2019 – wissenschaftliches Programm
O 45.5: Poster
Dienstag, 2. April 2019, 18:00–20:00, Poster D
High harmonic generation up to the keV regime and further applications of mid-infrared radiation — •Oscar Andres 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. Tabletop generation of soft x-rays pulses has become available using high harmonic generation driven by mid-infrared (MIR) femtosecond pulses in noble gases.
We developed a two-step Optical Parametric Chirped Pulse Amplifier that delivers sub 50 fs pulses at a wavelength of 3200 nm and energy >500 µJ as a pump for a tabletop soft x-ray source. That opens a door to perform a wide variety of soft x-ray experiments. Moreover, this MIR source also allows us to observe Floquet-Bloch states on the surfaces of topological insulators by femtosecond photoelectron spectroscopy. We present the achieved spatial, spectral and temporal pulse characteristics of the MIR source as well as the estimate soft x-ray flux with some of the applications to be developed.
This work is funded by the DFG through SFB 1242, TP A05.
 T. Popmintchev et al., Science 336, 1287 (2012).
 F. Mahmood et al., Nature Phys. 12, 306 (2016)