Ultrafast snapshots of a photo-induced phase transition


How fast an intense laser pulse can change the electrical state of a solid is revealed by researchers from the Institute of Experimental and Applied Physics in the current edition of Nature. Scientists in the team of Michael Bauer, Kai Rossnagel and Lutz Kipp, together with colleagues from the University of Kaiserslautern and the University of Colorado in Boulder, U.S.A., are following the course of electronic switching processes which occur within fractions of a second. In their time-resolved photoemission experiment using a laser-based light source in the extreme ultraviolet spectral regime, they observe the melting of a periodic charge order in TiSe2 taking place within less than 3*10-14 seconds. Currently, the technique developed for these studies is worldwide unique in its performance and promises in general very new insights into the physics of condensed matter systems on ultrashort time-scales.