Abstract

Filamentation is a complex process that gives rise to many nonlinear interactions. However, the fundamentals of filament formation and propagation can be explained in terms of two dominant mechanisms: Kerr self-focusing and plasma defocusing. The first to occur, self-focusing, is responsible for an increase in irradiance through beam collapse. This process requires sufficient initial peak power, on the order of gigawatts for near infrared beams in air. Plasma defocusing then arrests the collapse process once the irradiance reaches the ionization threshold of the medium. These two processes balance each other in an extended plasma channel known as a filament. A beam's collapse behavior is strongly influenced by the initial beam conditions, especially in applications that require power scaling to terawatt levels where the Kerr effect is more pronounced. Therefore, understanding and controlling the collapse process is essential in this regime. For this reason, an exploration of the wavefront evolution of filamenting beams is of great interest and the topic of this thesis, which has three parts. First, it reviews the filamentation process and describes characteristics of filaments. Next, experimental measurements of the wavefronts of filamenting beams are given in two separate regimes. The first regime is the Kerr self-focusing that takes place before beam collapse is arrested. This data is then contrasted with wavefront measurements within a filament after collapse has occurred.

Graduation Date

2017

Semester

Summer

Advisor

Richardson, Martin

Degree

Master of Science (M.S.)

College

College of Optics and Photonics

Department

Optics and Photonics

Degree Program

Optics and Photonics

Format

application/pdf

Identifier

CFE0006808

URL

http://purl.fcla.edu/fcla/etd/CFE0006808

Language

English

Release Date

August 2022

Length of Campus-only Access

5 years

Access Status

Masters Thesis (Campus-only Access)

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