Seeded free-electron laser driven by a compact laser plasma accelerator

Abstract Free-electron lasers generate high-brilliance coherent radiation at wavelengths spanning from the infrared to X-ray domains. The recent development of short-wavelength seeded free-electron now allows for unprecedented levels control on longitudinal coherence, opening new scientific avenues such as ultra-fast dynamics complex systems and nonlinear optics. Although those devices rely state-of-the-art large-scale accelerators, advancements laser-plasma which harness gigavolt-per-centimetre accelerating fields, showcase a promising technology compact drivers lasers. Using footprint-reduced exponential amplification shot-noise type in self-amplified spontaneous emission configuration was recently achieved. However, employing this approach delivery temporally pulses controlled manner has remained major challenge. Here we present experimental demonstration accelerator-driven laser configuration, where over wavelength is accomplished. Furthermore, appearance interference fringes, resulting interaction between phase-locked emitted seed, confirms coherence. Building our achievements, anticipate navigable pathway extreme-ultraviolet wavelengths, paving way towards smaller-scale lasers, unique tools multitude applications industry, laboratories universities.