Keywords

filamentation, atmospheric propagation, long-range filament propagation, low-pressure filamentation

Subject Categories

Aerospace Engineering | Optics | Physics

Abstract

Long-range laser applications are limited by the challenges associated with projecting sufficient intensities over meaningful distances through realistic atmospheric conditions. The atmosphere introduces numerous effects that degrade beam quality and induce energy loss, including turbulence, scattering, and other environmental effects. Some of these challenges may be overcome with the use of laser filaments. An intense ultrashort pulse propagates nonlinearly through the air and experiences a dynamic balance of Kerr self-focusing, plasma defocusing, and diffraction, resulting in the formation of a plasma channel and a region of high-intensity propagation referred to as a laser filament. Filaments can propagate for distances longer than the Rayleigh length and can reach intensities on the order or 1013 W/cm2 without the use of large focusing optics, making them attractive for long-range applications.

Since filamentation is a nonlinear process and therefore dependent on the medium through which it propagates, filament formation and propagation must be thoroughly characterized in realistic atmospheric conditions. While laser filaments have been well characterized in laboratory settings, this work aims to understand the dynamics of filament formation and propagation over long distances and in low-pressure environments. Long-range filamentation experiments were conducted on the 1-km propagation range at the Townes Institute for Science and Technology Experimentation Facility, where direct measurements of filament intensity profiles at distances up to 350 m were made for the first time. Additionally, low-pressure experiments were conducted using the High Energy Laser Atmospheric Chamber. The laser preconditions were carefully selected to ensure self-sustained filamentation at pressures ranging from 1 atm to 0.15 atm, corresponding to altitudes up to approximately 13 km. The results presented here advance the understanding of filamentation in realistic propagation conditions and demonstrate the feasibility of filamentation for long-distance or high-altitude applications.

Completion Date

2026

Semester

Summer

Committee Chair

Richardson, Martin

Degree

Doctor of Philosophy (Ph.D.)

College

College of Optics and Photonics

Department

Optics and Photonics PhD

Format

PDF

Document Type

Dissertation

Language

English

Release Date

8-15-2028

Download

Available for download on Tuesday, August 15, 2028

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