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Engineering And Application Of Ultrafast Laser Pulses And Filamentation In Air, Nicholas Barbieri
Engineering And Application Of Ultrafast Laser Pulses And Filamentation In Air, Nicholas Barbieri
Electronic Theses and Dissertations
Continuing advances in laser and photonic technology has seen the development of lasers with increasing power and increasingly short pulsewidths, which have become available over an increasing range of wavelengths. As the availability of laser sources grow, so do their applications. To make better use of this improving technology, understanding and controlling laser propagation in free space is critical, as is understanding the interaction between laser light and matter. The need to better control the light obtained from increasingly advanced laser sources leads to the emergence of beam engineering, the systematic understanding and control of light through refractive media and …
Femtosecond Filament Interaction As A Probe For Molecular Alignment, Erik Mckee
Femtosecond Filament Interaction As A Probe For Molecular Alignment, Erik Mckee
Electronic Theses and Dissertations
Femtosecond laser filamentation is a highly nonlinear propagation mode. When a laser pulse propagates with a peak power exceeding a critical value Pcr (5 GW at 800 nm in air), the Kerr effect tends to collapse the beam until the intensity is high enough to ionize the medium, giving rise to plasma defocusing. A dynamic competition between these two effects takes place leaving a thin and weakly ionized plasma channel in the trail of the pulse. When an ultrafast laser pulse interacts with molecules, it will align them, spinning them about their axis of polarization. As the quantum rotational wave …