Thesis Dissertation Defense

Abstract:

Short pulse (<10 ps), high-intensity (>1018 W/cm2) laser systems can be used to generate and probe extremely high energy and density conditions of matter. The plasmas produced by these high intensity laser systems can act as compact radiation sources, can emulate astrophysical phenomena like supernova and centers of giant planets, and even allow access to fusion regimes. Besides fundamental plasma physics, these ultraintense laser-matter interactions also lend themselves to impactful scientific applications, including renewable energy and state-of-the-art medical techniques.

A continuing fundamental need in the field of laser-driven High Energy Density (HED) and plasma physics is the accurate and precise spatial and temporal characterization of the laser pulse, which would provide valuable insight into the foundational physics that drive these interactions. Laser-plasma interactions are complex, rapidly evolving, and highly sensitive to shot-to-shot variations in laser parameters, such as laser peak intensity, pulse duration, pre-pulse, and focal spot, and/or thermal instabilities. Even under nominally identical laser conditions, small variations can drastically influence outcomes. However, in typical HED experiments currently, the complexity of the 4-D laser electric field E(x,y,z,t) can mean that the wavefront is not often characterized, or that it is characterized in a surrogate setup or surrogate shot. To accurately understand these interactions, on-shot experimental techniques must be established and implemented. I will discuss the development of a single-frame laser characterization diagnostic for novel use on high-intensity, low repetition rate laser systems, its adaptation to high-repetition rate (>Hz) laser systems, its use in diagnosing and optimizing an ultraintense laser system, and its role in developing a more complete understanding of the underlying laser-plasma interaction physics. Breakthroughs in these measurement capabilities can unlock an entirely new regime of experimental measurement, deliver a novel capacity to determine and assess pivotal factors that limit more precise control of laser-driven radiation sources, and serve as a necessary tool to improve laser-plasma interaction predictive capability.