Sub-fs pulse generation and characterisation in the VUV

摘要

It is nowadays possible to produce isolated attosecond pulses in the XUV photon energy range (∼90 eV) [1]. These can be employed in combination with infrared (IR) pulses in IR field dressed photo-ionisation experiments to investigate attosecond dynamics in XUV pump IR probe schemes [2]. Specific chromophores in large biomolecules have a high photo excitation cross-section in the VUV range (10–20eV) [3]. Therefore attosecond VUV pulses will enhance the excitation fraction of a molecular sample and allow direct atto-pump atto-probe experiments. We discuss how we plan to produce efficient HHG radiation in this range. The target is optimised to achieve high photon flux and a sub-fs pulse. We discuss the set up for an absolute measurement of the photon flux in combination with spectral and temporal characterisation of the pulse [4] necessary for such an optimisation. We discuss the modelling of the optimisation process according to phase matching calculations [5] and 2D/3D time dependent Schrödinger equation (TDSE) numerical simulations [6].