Loading...
Advanced spatiotemporal laser shaping for accelerator and free electron laser technology
Lemons, Randy Alan
Lemons, Randy Alan
Citations
Altmetric:
Advisor
Editor
Date
Date Issued
2023
Date Submitted
Keywords
Collections
Research Projects
Organizational Units
Journal Issue
Embargo Expires
Abstract
Spatiotemporal shaping of ultrashort laser pulses plays a crucial role the performance of radio frequency (RF) photocathodes and compact electron acceleration schemes such as dielectric laser acceleration and direct laser acceleration. In RF photocathodes, the quality of photo-emitted electrons is highly correlated to the laser's spatial and temporal intensity profile while compact accelerators require direct control over field parameters such as polarization and spatiotemporal wavefronts. In this thesis, I present two techniques, dispersion controlled nonlinear synthesis (DCNS) which focuses on temporal intensity shaping for RF photocathodes, and the universal light modulator (ULM) for full control over the spatiotemporal intensity, polarization, and wavefront profiles for compact sources.
DCNS generates picosecond duration laser pulses, a regime currently lacking any techniques for high-energy applications, via non-colinear sum frequency generation driven by highly dispersed femtosecond pulses with opposite chirps. This thesis focuses on a case study utilizing DCNS to generate a 20 picosecond pulse in the ultraviolet with a flattop temporal intensity profile for RF photocathodes driving x-ray free electron lasers. The theoretical improvements in photocathode performance of these pulses over conventional laser intensity profiles is discussed and a first-time experimental demonstration of DCNS is presented. Additionally, the custom-built numerical modeling tools for handling the nonlinear interactions involved with DCNS and their principles are discussed.
The ULM is a laser system allowing for the adaptive tailoring of the composite 3D spatiotemporal profile of an ultrashort optical pulse through the coherent combination of many individually controlled sub-lasers. This proof-of-principle system is built on a record-low carrier-envelope phase stable oscillator which drives seven sub-beams each with individual polarization, amplitude, phase, and timing control. The ability of this system to generate composite fields with individually programmable polarization, phase, and amplitude profiles in the near and far field is demonstrated. Additionally, a genetic algorithm-based phase reconstruction technique was developed to recover the parameters of the individual sub-beams from single images of the composite field.
Associated Publications
Rights
Copyright of the original work is retained by the author.