On the Role of Linear Processes in the Development and Evolution of Filaments in Air

It is well known that ultrashort, high intensity pulses with peak powers exceedinga certain critical value (Pcr) undergo self-focusingleading to collapse and filamentation. During the initial stagesof propagation at low intensities the beamdynamics are dominated by diffraction and dispersion. During filamentation, self-focusing resulting from the nonlinear Kerr effect is balanced by higher order nonlinearities such as plasma induced defocusing and absorption.This work examines the role that linear processes combined with initial spatial and temporal conditioningplay in the generation and subsequent evolution of filaments within nonlinearbeams. It is demonstrated that, because of linear diffraction, initial spatial beam shaping can have a dramatic effect on the filament pattern, the number of filaments and the energy contained in each filament. These ideas are applicable to cases that arequite common, such as circularly apodized beams, and help to explain interestingbehavior observed in these types of beams. Finally, it is demonstrated thatwith appropriate preconditioning of multiple subcritical pulses, linear effects can be employed to accurately control when and where filamentation occurs during long distance propagation through conditional collapse of overlapping pulses.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Optical Sciences

Grantor dc:publisher

The University of Arizona.

Year dc:date.issued

2007

Author dc:creator

• Roskey, Daniel Eric

Advisor dc:contributor.advisor

• Wright, Ewan M

Committee members dc:contributor.committeemember

• Wright, Ewan M.
• Maloney, Jerome V.
• Anderson, Brian P.
• Kolesik, Miroslav

• nonlinear optics
• filaments
• light strings
• filament control
• nonlinear schroedinger

Statement dc:rights

• Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/10150/194509

OAI identifier oai:identifier

oai:repository.arizona.edu:10150/194509