Laser-driven free-electron lasers use laser pulses instead of magnetostatic undulators, enabling x-ray amplification with lower electron energies and shorter interaction lengths. Here, the authors show that a flying-focus pulse, with an intensity peak moving opposite to its phase fronts, provides the uniformity needed for high-gain X-ray generation using 20 × less energy than conventional laser pulses
- D. Ramsey
- B. Malaca
- J. P. Palastro
