Phase resolved attosecond photoionization

by Dr Yann Mairesse (CELIA, Université Bordeaux I, France)

Thursday 19 May 2011, 11:00 → 12:00 Europe/Berlin

AER 19/3.11

High order harmonic generation is a natural source of trains of attosecond pulses in the extreme ultraviolet. The main technique used to characterize these attosecond pulses is the RABBITT technique (Resolution of Attosecond Beatings By Interference of Two-photon Transitions), in which a rare gas is photoionized by the attosecond pulse train in the presence of an additional weak infrared field. By controlling the delay between the infrared and the XUV light, it is possible to retrieve the relative phase of the different harmonics constituting the attosecond pulse train, and thus the temporal structure of the attosecond pulses. Alternatively, the RABBITT method can be used to characterize the photoionization process itself: using a well characterized attosecond pulse train to photoionize a more complex target (molecular gas, solid), information on the phase of the photoionization process can be retrieved. We will show how this method can be used to reveal a phase jump in the attosecond photoionization of nitrogen molecules in the vicinity of a resonance. We will also discuss the current extension of such measurements to the case of solid targets.