supported by the National Natural Science Foundation of China(Nos.11127901,11425418,61521093,11304271,11205228,and 11505263);the Strategic Priority Research Program(B)(No.XDB16);the Youth Innovation Promotion Association CAS;the State Key Laboratory Program of the Chinese Ministry of Science and Technology
Beam quality degradation during the transition from a laser wakefield accelerator to the vacuum is one of the reasons that cause the beam transport distortion, which hinders the way to compact free-electron-lasers. He...