Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 94: Ultrafast Surface Dynamics II
O 94.4: Talk
Friday, March 11, 2016, 11:30–11:45, S054
Novel light source for time- and angle-resolved photoelectron spectroscopy — •Michele Puppin1, Yunpei Deng2, Johannes Feldl1, Chris Nicholson1, Claude Monney3, Hendrik Vita1, Martin Wolf1, and Ralph Ernstorfer1 — 1Fritz-Haber Institut, Berlin, Germany — 2Paul-Scherrer Institut, Switzerland — 3University of Zurich, Switzerland
Time- and Angle- Resolved Photoemission Spectroscopy (tr-ARPES) accesses the out-of-equilibrium electronic band structure in the time domain and provides information on coupling and correlation effects between electronic and lattice degrees of freedom as well as on excited state dynamics. These studies benefit from the high counting statistics of light sources with 100s of kHz repetition rate. However, due to their low photon energy (< 6.3 eV), high repetition rate sources were limited so far to investigations at the Brillouin zone center. We have developed an efficient femtosecond source with 500 kHz repetition rate capable of tr-ARPES with XUV pulses, granting access the full Brillouin zone. The key component of this approach is an optical parametric chirped-pulse amplifier (OPCPA) providing intense 30 fs pulses. A simple monochromatization scheme allows selecting a single harmonic at 22.3 eV with 100 meV bandwidth with a photon flux exceeding 1011 photons/s. First proof-of-concept tr-ARPES data on transition metal dichalcogenides are presented.