Doctor of Philosophy (PhD)
The work presented in this dissertation will relate the photorecombination dynamics to photoionization dynamics in SF6 utilizing the self-probing mechanism, high harmonic generation (HHG). This work specifically aims to establish parameters for which the comparison is applicable and the macroscopic complications inherent in HHG do not interfere with the extraction of dynamic information. The first part of this work established the macroscopic experimental apparatus necessary for consistent spectroscopic observation. It is shown that using a gas jet that is an order of magnitude shorter than the Rayleigh length of the driving laser results in more consistent harmonic spatial profiles and location of spectroscopic features. The observation of photorecombination dynamic in HHG is extended to shape resonances in SF6 with a focus on separating the effects of phase matching from photorecombination. This is accomplished by varying the laser parameters including the location of the focal point with respect to the center of the gas jet and altering the strength of the electric field. This process allowed us to observe two high energy shape resonances in the HHG spectrum of SF6 and map the appropriate parameters at which our experimental results confirm theoretical calculations based on the quantitative rescattering theory conducted by collaborators at Texas A&M University. The shape resonance was then probed by adding ellipticity to the fundamental in order to determine if there was information related to the angular dependence of the shape resonance that could be extracted in a way unique to HHG.
Document Availability at the Time of Submission
Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.
Wilson, Benjamin Parker, "Investigating the Photorecombination Dynamics in Molecular High-Harmonic Spectra" (2015). LSU Doctoral Dissertations. 2210.