Regensburg 2013 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 11: Poster Session I: Application of thin films; Ion beam induced surface patterns; Ion and electron beam induced processes; Micro- and nanopatterning (jointly with O)
DS 11.8: Poster
Montag, 11. März 2013, 17:00–20:00, Poster B1
Generating ultrashort circularly polarized XUV pulses from gas high harmonics by means of a multilayer quarter-waveplate — •Jürgen Schmidt1, Alexander Guggenmos2, Niklas Mutz1, and Ulf Kleineberg1,2 — 1LMU München, Physik, 85748 Garching — 2Max-Planck-Institut für Quantenoptik, 85748 Garching
Coherent linearly polarized XUV pulses from High Harmonic Generation in noble gas are routinely used for ultrafast pump-probe experiments to examine electron dynamics in solids or gases. The availability of circularly polarized high harmonic pulses with selectable helicity would extend the possible spectroscopic methods applicable to those pulses towards electron spin dependant or circular dichroism experiments and would give access to the investigation of temporal electron spin dynamics on a time scale of 1 fsec or even below. However, current concepts which aim at generating ultrashort elliptically polarized pulses from gas harmonics directly promise only a small ellipticity. We thus designed, fabricated and tested ultrathin multilayer-based quarter wave retarders at a photon energy of 66.2eV (Ni-3p state) to transform linearly polarized XUV pulses into circularly polarizd pulses . We investigate the polarization state of the pulses and the transmission characteristics of the quarter waveplate by means of a Rabinovich-type polarimeter with a multilayer analyzer mirror and an XUV spectrometer. A trade-off between pulse duration (i.e bandwidth) and degree of ellipticity is discussed and future experimental application in time-resolved ARPES experiments is described.