Undergraduate Honors Theses

Thesis Defended

Spring 2015

Document Type


Type of Thesis

Departmental Honors


Engineering Physics

First Advisor

Dr. Henry Kapteyn

Second Advisor

Dr. Margaret Murnane


In this experiment, we propagate superposed 800 nm and 400 nm circularly polarized driving laser fields and interact the combined field with argon gas—in doing so, we demonstrate strong field ionization from this interaction. We then use velocity map imaging and tomographic reconstruction techniques to look at the resulting photoelectron angular distributions. From this, we discover that if the driving fields are counter-rotating, we see low energy structures which indicate rescattering of electrons off of their parent atoms. The presence of these low energy structures offers the first experimental verification of the theoretical model describing how circularly polarized high harmonics are generated. I discuss in this thesis: the concepts of high harmonic generation and strong field ionization, the interest in circularly polarized driving laser fields for producing circularly polarized high harmonics, applications of circular x-ray light, a detailed explanation of our experiment, the specific role that I played, our results, and current projects and extensions to this experiment that I am working on presently.