Optical Science and Engineering ETDs

Publication Date

Spring 5-15-2017

Abstract

Laser filaments are extremely interesting entities for their unique characteristics. The high intensity inside the laser filaments creates nonlinear effects that are useful in many areas of optics. The laser filamentation is an appealing tool in the stand-off spectroscopy for its ability to propagate over long distances while maintains its extreme intensity. However, depletion of energy hinders its propagation over any desired distance. In order to understand the effect of laser filaments on the transparent medium that they propagate through, one needs to investigate interaction of the laser filaments with the constituents of media. In this work we study the interaction of laser filaments with the molecular and atomic gaseous media. We try to separate the molecular and electronic responses of the media. Effect of laser polarization on the response of media is studied for linear and circular polarizations. Emission from the nitrogen molecules and ions pumped by the laser filaments is studied. We show that there are emission in the forward and backward directions from nitrogen gas when it is irradiated by strong pulses that go through filamentation. Effects of laser polarization are also considered by using circular and linear laser pulses.

We propose a technique to enhance the longevity of 800 nm laser filaments. By spatially combining the UV laser filaments that have low loss and longer propagation distance one can feed the energy reservoir of the IR laser filament through four-wave mixing. We theoretically study this beam combining and show that this scheme is viable and under tunable conditions the energy will flow from the UV filament to the IR filament.

Degree Name

Optical Science and Engineering

Level of Degree

Doctoral

Department Name

Optical Science and Engineering

First Committee Member (Chair)

Ladan Arissian

Second Committee Member

Jean-Claude Diels

Third Committee Member

James Thomas

Fourth Committee Member

Alejandro Aceves

Document Type

Dissertation

Language

English

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