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Production And Characterization Of Femtosecond-Laser-Induced Air Plasma, David R. Armbruster
Production And Characterization Of Femtosecond-Laser-Induced Air Plasma, David R. Armbruster
Theses and Dissertations
The purpose of this research was to produce, characterize, and optimize laser induced air plasma as a preliminary step in using the plasma as a source of terahertz radiation. An 800 nanometer, 50 femtosecond, 0.75 Watt, pulsed Ti:Sapphire laser system was used as the source infrared beam. A beam expander was used to expand the beam to a diameter of approximately 6.5 mm, and the beam was focused through a 25 mm focal length achromatic lens to produce laser-induced plasma in ambient air. A 40 kHz ultrasonic transducer was used to detect the plasma. A second harmonic generation crystal was …
Portable Diode Pumped Femtosecond Laser, David A. Jones
Portable Diode Pumped Femtosecond Laser, David A. Jones
Theses and Dissertations
This thesis discusses the work to make ultrashort pulsed lasers smaller and more economical. While sharing many of the basic properties of normal beam optics there are some specific properties in both creating and exploiting those pulses that must be understood. The discussion will focus on mode locking as the primary way of producing ultrashort pulses. Particular attention will be paid to intracavity group velocity dispersion and how to correct it inside the cavity. The discussion then turns to the basis of our work including initial cavity design and component selection with focus on the specific crystals used in the …
A Study Of Collapse Events In Ultraviolet Light Filaments Due To Transient Edge Effects, Paul L. Muller
A Study Of Collapse Events In Ultraviolet Light Filaments Due To Transient Edge Effects, Paul L. Muller
Theses and Dissertations
Intense, short light pulses can form filaments capable of propagating kilometers through the atmosphere. This is due to the nonlinear index of refraction of the atmosphere in response to the pulse's high intensity, which creates a self-focusing effect that further intensifies the pulse. This focusing is balanced by the formation of defocusing plasma by the pulse. A split-step propagation model was used to simulate the propagation of these pulses through the atmosphere and investigate the collapse of long ultraviolet pulses of 10-100 picoseconds in duration due to transient edge effects. The structures of individual collapse events in the pulse were …