First demonstration of a staged all-optical laser wakefield acceleration

A proof-of-principle experiment on staged all-optical laser wakefield acceleration was performed at the Naval Research Laboratory. Electrons with <1MeV energy created by the interaction of a 2TW laser beam with a nitrogen gas jet were injected and accelerated to more than 20MeV in a plasma wakefield generated by a 10TW laser beam in a helium gas jet. The energy gain occurred in a narrow time window of 3ps between the injection and acceleration laser beams, and within a tight spatial alignment of ∼10μm.