Speaker
Description
Attosecond pulses from X-ray free-electron lasers (XFELs) have opened the doors to atomic site-specific studies of the motion of electrons on their natural timescales. Attosecond XFEL experiments to date have operated in the impulsive regime, in which the incoming pulse is short enough that the exact pulse duration and structure does not affect the system dynamics. On the other hand, structured pulses with tunable spectrotemporal shapes allow us to push the bounds of our models of quantum systems and pursue coherent control schemes in the ultrafast, X-ray driven regime. I will discuss two types of attosecond pulse shaping in which an isolated attosecond pulse generated in one set of undulators is shaped in a second stage. In the first, I will show how undulator tapering can be translated into versatile control of the spectrotemporal structure of an FEL seeded by a short pulse. I give an example of experimental evidence of the production of mutually coherent attosecond pulse trains. In the second method, I show how leveraging microbunching generated in the first stage enables the production of mutually coherent attosecond pulse pairs. I show direct time-domain evidence that pulse pairs can be produced and that their relative time delay and phase are both stable and tunable.
| Working group | WG6 |
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