Date of Award

Spring 1-1-2017

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

First Advisor

Margaret M. Murnane

Second Advisor

Henry C. Kapteyn

Third Advisor

Andreas Becker

Fourth Advisor

Xiaobo Yin

Fifth Advisor

W. Carl Lineberger

Abstract

Recent advances in the generation and control of attosecond light pulses have opened up new opportunities for the real-time observation of sub-femtosecond (1 fs = 10-15 s) electron dynamics in gases and solids. Combining attosecond light pulses with angle-resolved photoelectron spectroscopy (atto-ARPES) provides a powerful new technique to study the influence of material band structure on attosecond electron dynamics in materials. Electron dynamics that are only now accessible include the lifetime of far-above-bandgap excited electronic states, as well as fundamental electron interactions such as scattering and screening. In addition, the same atto-ARPES technique can also be used to measure the temporal structure of complex coherent light fields. In this thesis, I present four experiments utilizing atto-ARPES to provide new insights into the generation and characterization of attosecond light pulses, as well as the attosecond electron dynamics in transition metals. First, I describe a new method to extend attosecond metrology techniques to the reconstruction of circularly polarized attosecond light pulses for the first time. Second, I show that by driving high harmonics with a two-color linearly polarized laser field, quasi-isolated attosecond pulses are generated because the phase matching window is confined. Third, I present the first measurement of lifetimes for photoelectrons that are born into free-electron-like states compared with those that are excited into unoccupied excited states in the band structure of a material (Ni(111)). The finite excited-state lifetime causes a ≈200 as delay in the emission of photoelectrons. Finally, I describe direct time-domain studies of electron-electron interactions in transition metals with both simple and complex Fermi surfaces. In particular, I show the influence of electron-electron scattering and screening on the lifetime of photoelectrons.

Available for download on Tuesday, August 28, 2018

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