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Atomic and Molecular Dynamics Probed by Intense Extreme Ultraviolet Attosecond Pulses

Peschel, Jasper LU (2021)
Abstract
This thesis work was aimed to investigate dynamical processes in atoms and molecules on ultrafast time scales initiated by absorption of light in the extreme ultraviolet (XUV) regime. In particular, photoionization and photodissociation have been studied using pump-probe techniques involving ultrafast laser pulses. Such pulses are generated using either high-order harmonic generation (HHG) or free-electron lasers (FELs).

The work of this thesis consists to a large extent in the development and application of a light source, enabling intense XUV attosecond pulses using HHG. In a long focusing geometry, a high-power infrared laser is frequency up-converted so as to generate a comb of high-order harmonics. An important aspect was the... (More)
This thesis work was aimed to investigate dynamical processes in atoms and molecules on ultrafast time scales initiated by absorption of light in the extreme ultraviolet (XUV) regime. In particular, photoionization and photodissociation have been studied using pump-probe techniques involving ultrafast laser pulses. Such pulses are generated using either high-order harmonic generation (HHG) or free-electron lasers (FELs).

The work of this thesis consists to a large extent in the development and application of a light source, enabling intense XUV attosecond pulses using HHG. In a long focusing geometry, a high-power infrared laser is frequency up-converted so as to generate a comb of high-order harmonics. An important aspect was the study of the spatial and temporal properties of the generated light pulses in order to gain control of their influence on the experiment. Combining theoretical and experimental results, the effect of the dipole phase on properties of high-order harmonics was explored, along with a metrological series of studies on the harmonic wavefront and the properties of the focusing optics used.

Further, the HHG light source was employed to investigate photoionization. Individual angular momentum channels involved in the ionization were characterized using two-photon interferometry in combination with angle-resolved photoelectron detection. A method is applied allowing the full determination of channel-resolved amplitudes and phases of the matrix elements describing the single-photon ionization of neon.

Finally, the process of photodissociation was investigated using light pulses generated via both HHG and FELs. The dissociation dynamics induced by multiple ionization of organic molecules were studied. Correlation techniques were used to unravel the underlying fragmentation dynamics, and additionally, pump-probe experiments provided insights into the time scales of the (pre-)dissociation dynamics.
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Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Prof. Biegert, Jens, ICFO - The Institute of Photonic Sciences, Spain.
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Attosecond science, Ultrafast phenomena, High-order Harmonics Generation, Free Electron Lasers, Photoionization, Photodissociation, Fysicumarkivet A:2021:Peschel
pages
296 pages
publisher
Atomic Physics, Department of Physics, Lund University
defense location
Lecture Hall Rydbergsalen, Department of Physics, Professorsgatan 1, Faculty of Engineering LTH, Lund University, Lund. Zoom: https://lu-se.zoom.us/j/69911962368?pwd=Q0h4aXVoQUpPQld6MUovMFZkckpVdz09
defense date
2021-10-15 09:15:00
ISBN
9789180390156
language
English
LU publication?
yes
id
6a5eb6f4-32a2-40f4-b036-6ed1bc16f32f
date added to LUP
2021-09-15 12:47:48
date last changed
2022-04-12 13:46:27
@phdthesis{6a5eb6f4-32a2-40f4-b036-6ed1bc16f32f,
  abstract     = {{This thesis work was aimed to investigate dynamical processes in atoms and molecules on ultrafast time scales initiated by absorption of light in the extreme ultraviolet (XUV) regime. In particular, photoionization and photodissociation have been studied using pump-probe techniques involving ultrafast laser pulses. Such pulses are generated using either high-order harmonic generation (HHG) or free-electron lasers (FELs).<br/><br/>The work of this thesis consists to a large extent in the development and application of a light source, enabling intense XUV attosecond pulses using HHG. In a long focusing geometry, a high-power infrared laser is frequency up-converted so as to generate a comb of high-order harmonics. An important aspect was the study of the spatial and temporal properties of the generated light pulses in order to gain control of their influence on the experiment. Combining theoretical and experimental results, the effect of the dipole phase on properties of high-order harmonics was explored, along with a metrological series of studies on the harmonic wavefront and the properties of the focusing optics used. <br/><br/>Further, the HHG light source was employed to investigate photoionization. Individual angular momentum channels involved in the ionization were characterized using two-photon interferometry in combination with angle-resolved photoelectron detection. A method is applied allowing the full determination of channel-resolved amplitudes and phases of the matrix elements describing the single-photon ionization of neon.<br/><br/>Finally, the process of photodissociation was investigated using light pulses generated via both HHG and FELs. The dissociation dynamics induced by multiple ionization of organic molecules were studied. Correlation techniques were used to unravel the underlying fragmentation dynamics, and additionally, pump-probe experiments provided insights into the time scales of the (pre-)dissociation dynamics.<br/>}},
  author       = {{Peschel, Jasper}},
  isbn         = {{9789180390156}},
  keywords     = {{Attosecond science; Ultrafast phenomena; High-order Harmonics Generation; Free Electron Lasers; Photoionization; Photodissociation; Fysicumarkivet A:2021:Peschel}},
  language     = {{eng}},
  publisher    = {{Atomic Physics, Department of Physics, Lund University}},
  school       = {{Lund University}},
  title        = {{Atomic and Molecular Dynamics Probed by Intense Extreme Ultraviolet Attosecond Pulses}},
  url          = {{https://lup.lub.lu.se/search/files/102513382/opponent_ex_Jasper.pdf}},
  year         = {{2021}},
}