Speaker
Description
Plasma-based accelerators allow to boost the electron beam energy within a few centimeters. Two pioneering experiments [1,2], reporting the observation of self-amplified spontaneous emission (SASE) driven by plasma-accelerated beams, have already demonstrated their potential use for the realization of ultracompact light sources based on free-electron lasers (FELs).
However, the stochastic nature of the SASE process, together with the beam instabilities from the plasma acceleration process, lead to the lack of stability and reproducibility of the generated FEL pulses and may hinder their effective implementation for user purposes.
A proof-of-principle experiment [3], using plasma-accelerated beams seeded by an external laser in the infrared range, has been also implemented. A slightly off-resonance seed laser with respect to the undulator resonance was employed for this experiment, allowing to seed the FEL process with an emission wavelength following the resonant condition set by the undulator and to easily discriminate between the seed and FEL light spectra.
Here, the main results of FEL lasing in this configuration, showing the enhanced pulse energy and stability compared to SASE, are discussed.
[1] W.Wang et al., Nature 95, 516 (2021).
[2] R.Pompili et al., Nature 605, 659 (2022).
[3] M.Galletti et al., Physical Review Letters 129, 234801 (2022).
