Attosecond Probing of Atomic and Solid-State Dynamics

Steve Leone

Departments of Chemistry and Physics and Lawrence Berkeley National Laboratory, University of California, Berkeley

A new method of investigating atomic and solid-state materials involves laser pump-probe measurements in the extreme ultraviolet (XUV) with attosecond light pulses produced by the process of high harmonic generation. Such radiation interrogates core level spectroscopic transitions, which are element and oxidation state specific. In atoms and small molecules, a technique of attosecond four wave mixing provides a background-free way of measuring extremely short decay times and electronic and vibrational superpositions. In solids, electronic excitation provides a platform to investigate fundamental aspects of charge carrier dynamics explored from the viewpoint of specific elements. Materials topics include semiconductor band gap excitation, phase transitions, transport across junctions, and core-level excitons in 2D metal dichalcogenides. Dynamics measurements in the extreme ultraviolet provide a novel and powerful probe for nonequilibrium states of matter.