A hybrid quantum-classical approach to the interaction of atomic clusters with intense laser fields in the vacuum ultra-violet (VUV) has been developed. Much emphasis is put on localized electrons, those quasi-free electrons which localize about the ions and screen them. These electrons set a time scale, which is used to interpolate between the quantum, rate based description of photon absorption by bound electrons and the classical, deterministic description of the cluster nano-plasma. Typical observables such as total energy absorption, electron and ion spectra are in very good agreement with the experimental findings. A scheme to probe the multi-electron motion in clusters with attosecond laser pulses is introduced. Conventional final state measurements in the energy domain cannot provide information about earlier states of the system due to the incoherent nature of the dynamics. Time-delayed attosecond pulses in the extreme ultra-violet (XUV) are used to probe the transient charging of the cluster ions during the interaction with the laser by measuring the kinetic energy of the electrons detached by the probe pulse. This information is otherwise lost at later times due to recombination. Knowledge about the transient charging would also shed more light on the still controversial subject of the energy absorption mechanisms in the VUV regime. Moving to shorter duration of the excitation, the characteristic time-scales for ionization and plasma equilibration are inversed. An attosecond laser pulse in the VUV regime creates a dense, warm nano-plasma far from equilibrium. Time-delayed attosecond pulses in the XUV probe then both the creation and the relaxation. The latter shows the breakup of the Bogoliubov hierarchy of characteristic times, indicating strongly-coupled plasma dynamics and drawing parallels to the relaxation of extended ultra-cold neutral plasmas with millions of particles.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:24072 |
| Date | 28 July 2008 |
| Creators | Georgescu, Ionut |
| Contributors | Rost, Jan-Michael, Reinhard, Paul-Gerhard, Schmidt, Rüdiger |
| Publisher | Technische Universität Dresden |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
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