TY - THES
AU - Joel Venzke
AB - The development of ultrashort laser pulses with durations of a few tens of attoseconds (1 as = 10−18 s) has opened the possibility of observing and controlling the motion of electrons in matter at their natural time scale. However, the broad spectral bandwidth of the pulses pose the challenge that several linear and nonlinear pathways compete and interfere during the interaction of those pulses with the target. The ionized electrons contain information about the target, the electronic wavepacket prior to ionization, the laser pulse, and the various pathways to ionization. In this thesis, we will use numerical and analytic tools to study and interpret these ionization spectra. Additionally, we will examine electron excitation to Ryberg states driven by intense IR pulses and discuss the tools we are developing to study electron correlation.
First, we will give a brief review of ultrafast and ultrastrong physics literature. This is fol-lowed by an overview of the numerical and analytic methods used in this thesis including our recent insights in frequency corrections for short pulses and work on using radial basis functions to solve the time-dependent Schr¨odinger equation. We then focus on few photon ionization including effects induced by ultrashort pulses, the development of novel generalized asymmetry parameters, and the reconstruction of electronic wavepackets undergoing attosecond motion. Next, we present theoret-ical studies concerning the analysis of excitation and stabilization effects related to Rydberg states in the case of both linear and bi-circular laser pulses. Finally, we will discuss the development and first tests of a fully correlated two-electron code that utilizes a basis of hyperspherical harmonics.
BT - Department of Physics
CY - Boulder
DA - 2021-04
N2 - The development of ultrashort laser pulses with durations of a few tens of attoseconds (1 as = 10−18 s) has opened the possibility of observing and controlling the motion of electrons in matter at their natural time scale. However, the broad spectral bandwidth of the pulses pose the challenge that several linear and nonlinear pathways compete and interfere during the interaction of those pulses with the target. The ionized electrons contain information about the target, the electronic wavepacket prior to ionization, the laser pulse, and the various pathways to ionization. In this thesis, we will use numerical and analytic tools to study and interpret these ionization spectra. Additionally, we will examine electron excitation to Ryberg states driven by intense IR pulses and discuss the tools we are developing to study electron correlation.
First, we will give a brief review of ultrafast and ultrastrong physics literature. This is fol-lowed by an overview of the numerical and analytic methods used in this thesis including our recent insights in frequency corrections for short pulses and work on using radial basis functions to solve the time-dependent Schr¨odinger equation. We then focus on few photon ionization including effects induced by ultrashort pulses, the development of novel generalized asymmetry parameters, and the reconstruction of electronic wavepackets undergoing attosecond motion. Next, we present theoret-ical studies concerning the analysis of excitation and stabilization effects related to Rydberg states in the case of both linear and bi-circular laser pulses. Finally, we will discuss the development and first tests of a fully correlated two-electron code that utilizes a basis of hyperspherical harmonics.
PB - University of Colorado Boulder
PP - Boulder
PY - 2021
EP - 174
T2 - Department of Physics
TI - Theoretical studies on imaging of electron motion and excitation on ultrafast time scales
VL - Ph.D.
ER -