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Ultrashort Pulse Laser Filamentation Electrical And Optical Diagnostic Comparison, James E. Wymer
Ultrashort Pulse Laser Filamentation Electrical And Optical Diagnostic Comparison, James E. Wymer
Optical Science and Engineering ETDs
Results presented here examine the effect of changing gas pressure on the radio frequency (RF) emissions of an ultrashort pulse laser filament plasma and how those emissions vary longitudinally in the laser focal region. We use a WR284 rectangular waveguide with a 1.5 cm hole that allows the beam through. A 3.2 GHz microwave signal is emitted in the waveguide, and signals are received through a waveguide-to-coax antenna connected to an HP8470B Schottky diode. By enabling and disabling the 3.2 GHz signal, we measure both the self-emitted RF from a USPL filament and subsequently the degree of attenuation a filament …
Ultrafast Spectroscopy Of Air Lasing In Filaments, Brian Robert Kamer
Ultrafast Spectroscopy Of Air Lasing In Filaments, Brian Robert Kamer
Optical Science and Engineering ETDs
Filamentation in air is a phenomenon that has been extensively investigated for the last two decades. At sufficiently high intensity, even air is a nonlinear medium. These intensities are reached with ultrashort pulses (50 to 100 fs) of more than 1 J energy, which self-focus in air, reach ionizing intensities of oxygen and nitrogen, creating a plasma that defocuses the beam. The air filament is a self-induced waveguide resulting from a balance of focusing and defocusing. In this work new techniques were developed to visualize and analyze this phenomenon through its emission, in particu- lar the UV emission of the …
Synchronous Generation And Coherent Control Of Extreme Wavelength Radiation And Ultrafast Spectroscopy, Aram Gragossian
Synchronous Generation And Coherent Control Of Extreme Wavelength Radiation And Ultrafast Spectroscopy, Aram Gragossian
Optical Science and Engineering ETDs
Recent progress in ultrafast laser science has made it possible to synthesize and control complex electromagnetic waveforms down to sub-femtosecond timescales. These tailored ultrashort laser pulses can generate coherent bursts of electromagnetic radiation in the extreme ultraviolet (XUV) and terahertz spectral regions with durations reaching the attosecond regime in the XUV region. This is accomplished by coherently controlling electronic motion in gas plasma targets. With these novel radiation sources, ultrafast time-resolved spectroscopy can be performed on a large variety of materials. Knowledge of the spectral phase of an ultrashort pulse is crucial for many applications. There are a variety of …