Attosecond Soft X-ray Spectroscopy of Condensed Phase Matter

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The project will extend the technique of attosecond X-ray absorption spectroscopy to condensed phase materials. This will require further optimization of the required optical sources i.e. both the "pump" which are few-femtosecond long pulses in the visible to deep UV range, and the "probe" which are soft X-ray isolated attosecond pulses in the 100 - 500 eV photon energy range. For the former the research will focus on using non-linear optical methods to efficiently generate low order (up to 9th) of few-cycle pulses in the visible-NIR region. For the latter the present source, based on HHG of MIR few-cycle pulses in high density gas jets, will be enhanced by the use of optimized gas jet design and improved X-ray transmission through the beamline. With this capability we will measure exciton dynamics in organic polymers and organic oligomers in liquid phase to better understand fundamental issues of decoherence and transport of excitons in these materials. The role of polymer structure and morphology of the samples will be systematically explored. In this way not only will the research further the tools of ultrafast X-ray measurement, but may also contribute to the understanding of important materials in polymer opto-electronics that are currently used in solar energy harvesting research.