Controlled electron injection into a laser-driven wakefield at a well defined space and time is reported based on particle-in-cell simulations. Key novel ingredients are an underdense plasma target with an up-ramp density profile followed by a plateau and a fairly large laser focus diameter that leads to an essentially one-dimensional (1D) regime of laser wakefield, which is different from the bubble (complete blowout) regime occurring for tightly focused drive beams. The up-ramp profile causes 1D wave breaking to occur sharply at the up-ramp-plateau transition. As a result, it generates an ultrathin (few nanometer, corresponding to attosecond duration), strongly overdense relativistic electron sheet that is injected and accelerated in the wakefield. A peaked electron energy spectrum and high charge (∼nC) distinguish the final sheet.
- dense attosecond electron sheets
- laser wakefields
- up-ramp density transition
Li, F. Y., Sheng, Z. M., Liu, Y., Meyer-ter-Vehn, J., Mori, W. B., Lu, W., & Zhang, J. (2013). Dense attosecond electron sheets from laser wakefields using an up-ramp density transition. Physical Review Letters, 110(13), . https://doi.org/10.1103/PhysRevLett.110.135002