Scientists propose novel self-modulation scheme in seeded free-electron lasers   March 11, 2021 Seeded free-electron lasers (FELs), which use the frequency up-conversion of an external seed laser to improve temporal coherence, are ideal for providing fully coherent soft x-ray pulses. However, it is difficult to operate seeded FELs at a high repetition rate due to the limitations of present state-of-the-art laser systems. Researchers in China have developed self-modulation method for enhancing laser-induced energy modulation, thereby significantly reducing the requirement of an external laser system. They have experimentally realized high harmonic generation in a seeded FEL using an unprecedentedly small external laser-induced energy modulation. The results pave a way for […]