Undergraduate Honors Theses

Thesis Defended

Fall 2015

Document Type

Thesis

Type of Thesis

Departmental Honors

Department

Physics

First Advisor

Agnieszka Jaron-Becker

Second Advisor

Andreas Becker

Third Advisor

James Thompson

Fourth Advisor

Daniel Jones

Abstract

When bound electrons are exposed to high intensity, near-infrared light they radiate at integer multiples of the driving field’s frequency. The emitted light can reach into the extreme ultraviolet and soft x-ray region of the electromagnetic spectrum. Since the emitted frequencies are high and confined to integer multiples of the driving field’s frequency, this process is called High Harmonic Generation. The accepted semi-classical model for this process, given a linearly polarized driving field, was developed by P. B. Corkum. It is called the "Three Step Model" and it divides High Harmonic Generation by three major events: ionization, acceleration, and recombination. The model was expanded to omega - 2 omega non-linear field mixing by Milosevic et al. but the new model requires a long tunnel exit with a non-zero exit velocity. The values of momentum and time are saddle points for the quasi-classical action at the time of ionization and recombination. These saddle points could be used for calculating the spectrum of HHG, they are connected with critical times in the Three Step Model; and, in this thesis, they are used to determine potential electron trajectories. In this thesis I calculated saddle points, electric fields, quiver radii: alpha, ponderomotive energies: Up, and electron trajectories for a selection of driving fields. I varied the ratio of intensities in omega - 2 omega field mixing, and calculated maximum classically predicted harmonics for each combination.

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