Abstract: | The interaction of intense light with atoms or molecules can lead to the generation of extreme ultraviolet (XUV) pulses and energetic electron pulses of attosecond (10-18) duration. The advent of attosecond technology opens up new fields of time-resolved studies in which transient electronic dynamics can be studied with a temporal resolution that was previously unattainable. I will review the main challenges and goals in the field of attosecond science. As an example, I will focus on a recent experiment where the dynamics of tunnel ionization – one of the most fundamental strong-field phenomena – were studied. Specifically, we were able to measure the times when different electron trajectories exit from under the tunneling barrier created by a laser field and the atomic binding potential. In the following stage, subtle delays in ionization times from two orbitals in a molecular system were resolved. This experiment provides an additional, important step towards achieving the ability to resolve multielectron phenomena -- a long-term goal of attosecond studies. In the next part of my talk I will describe how we can proceed directly from measurement to control. In this study we link the generation process of attosecond pulses to the field of caustics - a unique type of singularity that is common to all wave phenomena. We demonstrated that caustics can appear in attosecond processes and showed that they offer a deeper understanding of the basic mechanism. |