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12THz-I-8
Mapping ultrafast ionization of atoms and clusters with terahertz field driven streak-camera
M. Krikunova1
1ELI Beamlines, Institute of Physics Academy of Sciences of the Czech Republic, Dolni Brezany, Czech Republic
Any target exposed to the focus of the intense extreme ultra-violet (XUV) or X-ray laser beam will be transformed into highly excited non-equilibrium states. Capturing the ultrafast ionization dynamics of a sample is crucial for the understanding of multiphoton and nonlinear X-ray physics phenomena. An experimental access to these ultra-short time scales is very challenging because it requires methods able to look inside of intense ultra-short XUV pulses. We use the terahertz (THz) field driven streak-camera concept to map the complex temporal structure of individual XUV pulses as well as to study multi-electron dynamics in clusters and nano-particles upon illumination by these XUV pulses [1,2].
In the THz-streaking experiment the THz field acts on the free electrons in the continuum. The effect can be understood as an additional momentum acquired by the free electrons in the presence of the oscillating electric field. By changing the time-delay between the ionizing XUV pulse with respect to the THz-streaking field and measuring the electron kinetic energy spectra, a streaking spectrogram is obtained. In the streaking experiment half of the oscillation period of the streaking field has to be shorter than the temporal width of the electron distribution. Therefore, to resolve the electron dynamics that is initiated by the femtosecond XUV pulse, a THz-field is used.
In this contribution we resent our recent investigations based on the THz-field driven streak camera concept [1,2]. We discuss the implementation of the THz-radiation for studies of ultra-fast processes at the ELI-Beamlines near Prague, in the Czech Republic - the international user facility that is currently approaching the user-operation. We present the current status of the multi-purpose user end-station (MAC) for experiments in atomic, molecular, and optical sciences and coherent diffractive imaging that is developed for advanced photon science experiments on low density targets (atoms, molecules, clusters, nano-particles and aerosols) in a broad range of the electromagnetic spectrum from THz to XUV [3].
References
[1] T. Oelze et al, Sci. Rep., 7, 40736 (2017).
[2] T. Oelze et al, Phys. Rev. A, 99, 043423 (2019).
[3] E. Klimesova et al, Sci. Rep. 9, 8851 (2019).
