Speaker
Description
Free-electron lasers (FELs) probe matter at the sub-atomic scale through coherent pulses with sub-ångström wavelengths and sub-femtosecond durations, but the high-energy beams driving them have traditionally required large radio-frequency accelerators with a sizeable footprint. Plasma-based acceleration, with gradients up to three orders of magnitude higher, opens the way to far more compact machines, and recent years have seen the first FEL signals from both laser-driven wakefield accelerators and beam-driven schemes. Using the SPARC_LAB test facility at INFN-LNF Frascati as a guiding thread, this talk retraces the journey from conventional to plasma-driven FELs, centred on two milestones achieved there: the first FEL lasing driven by a compact, few-centimetre beam-driven plasma accelerator, and its subsequent stable operation in a seeded configuration. Looking ahead, I will present EuPRAXIA@SPARC_LAB, the compact plasma-driven FEL user facility now under construction at LNF.