Probing ultrafast electron dynamics in condensed matter with attosecond photoemission

摘要

We discuss experiments that address the ultrafast dynamics inherent to the photoemission process in condensed matter. In our experimental approach, an extreme ultraviolet attosecond light pulse launches photoelectron wave packets inside a solid. The subsequent emission dynamics of these photoelectrons is probed with the light field of a phase-stabilized near-infrared laser pulse. This technique is capable of resolving subtle emission delays of only a few attoseconds between electron wave packets that are released from different energy levels of the crystal. For simple metals, we show that these time shifts may be interpreted as the real-time observation of photoelectrons propagating through the crystal lattice prior to their escape into vacuum. The impact of adsorbates on the observed emission dynamics is also investigated.