Attosecond-scale measurement of Wigner time delay in molecular photoionization

The photoelectric effect is one of the most fundamental light-matter interactions, which is widely used in probing ultrafast dynamics in atoms, molecules and condensed matters. It has been in the research spotlight for more than 100 years and most of its natural aspects are well-understood. However, the basic questions about how long the photoionization process takes and how to identify the specific mechanisms responsible for the measured time delay are open and debated.