Ole Rømer Colloquium Wednesday 26 September at 15.15 in Fys. Aud. Speaker: Pascal Salieres Lasers, Interactions and Dynamics Laboratory (LIDYL, CEA - Saclay, France Host: Lars Bojer Madsen Title: Using attosecond light pulses to clock electron emission Abstract: The recent generation of attosecond light pulses (1 attosecond = 10-18 s) has opened the possibility to track in time the fastest dynamics in matter. Of particular interest are the electron dynamics since they occur naturally on such a short timescale. Attosecond spectroscopy is thus able to shed new light on fundamental electronic processes involved in a variety of physical, chemical and biological reactions. An example is the photoelectric effect, the theory of which earned Albert Einstein the Nobel Prize, where the absorption of a quantum of light (the photon) induces the quasi-simultaneous emission of a photo-electron. Attosecond pulses have recently allowed the measurement of tiny delays between photon absorption and electron emission in a variety of atoms, molecules and solids. When ionization occurs in the vicinity of a resonance, the -possibly multielectronic- dynamics is strongly perturbed. It is now possible to resolve in time the build-up of resonance lineshapes, e.g., for Fano resonances, evidencing how photoelectron wavepackets are born and morph into asymmetric Fano profiles. During this Colloquium, I will explain how attosecond pulses can be generated and applied in attosecond photoionization spectroscopy, with a special emphasis on the above example. Coffee and cake will be available from 15.05