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Title: Laser-plasma interaction experiments using high energy, high contrast OPCPA lasers
Author: Robinson, Timothy
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2018
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A high-energy, high-contrast short-pulsed laser system using optical parametric chirped pulse amplification has been demonstrated as a platform for performing high intensity laser-matter interaction experiments. The existing Cerberus laser system at Imperial College was upgraded to include an improved stretcher system in its long-pulse OPCPA pump chain, and new optical parametric amplifier stages, including a high-energy single-shot stage, were designed, with the aim of achieving multi-terawatt power levels with optical parametric amplification alone once the upgrade is completed. A high-performance optical-limiter for protection of sensitive optical detectors was developed and characterized, and shown to provide orders of magnitude better performance than other systems reported in the literature. This setup was then modified for use as a supercontinuum light source, analyzed for its spectral stability properties, and shown to be stable in comparison to other supercontinuum sources reported in the literature. A laser pulse contrast diagnostic system incorporating the optical limiter into its architecture was designed, intended to allow measurement over high dynamic ranges and long timescales. An additional diagnostic for time-resolved absolute measurement of strong electromagnetic pulses from laser-plasma interactions using the linear electro-optic effect was demonstrated for the first time in the petawatt-regime. This system was tested at Vulcan Petawatt and shown to have favourable experimental noise characteristics in comparison to conventional EMP diagnostics. Furthermore, the electro-optic diagnostic was used to investigate the effects of target geometry on laser-driven EMP generation in the context of experiments with an ion-acceleration component.
Supervisor: Smith, Roland ; Hopps, Nicholas Sponsor: Engineering and Physical Sciences Research Council ; Atomic Weapons Establishment
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral