Speaker
Description
Generating high-brightness electron beams with optimized longitudinal phase space is essential for driving next-generation free-electron lasers (FELs). However, accelerator-induced distortions often degrade beam quality and lasing performance. Here, we present a novel approach to counteract these effects by manipulating the photoemission laser’s temporal distribution. By introducing a controlled longitudinal ramp to a flattop profile via spatiotemporal shaping of the UV photocathode laser, we achieved deterministic phase space control at the LCLS-II superconducting injector. We demonstrate that this tailored optical asymmetry acts as a pre-compensation mechanism for downstream resistive wall wakefields at ~80 pC. This effectively linearizes the phase space and suppresses nonlinear energy chirp, which is the critical requirement for optimal FEL performance. These findings establish upstream spatiotemporal laser shaping as a powerful tool for directly optimizing FEL beam brightness at the source.
Zhou et al., PRAB 24, 073401 (2021)
**Zhang et al., arXiv:2601.03580 (2026)
Lemons et al., Ultrafast Sci. 5, 0112 (2025)
Funding Agency
Work supported by DOE BES under DE-AC02-76SF00515, DE-SC0022559, DE-FOA-0002859, DE-FG02-86ER13491; NSF 2231334, 2431903, 2436343; AFOSR FA9550-23-1-0409.
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