Improvement of the stability of laser accelerated electron bunch using counter-crossing and head-on laser pulses

Kotaki, Hideyuki; Daito, Izuru; Kando, Masaki; Hayashi, Yukio; Kawase, Keigo; Kameshima, Takashi; Fukuda, Yuji; Homma, Takayuki; Ma, J.*; Chen, L. M.*; Esirkepov, T. Z.; Pirozhkov, A. S.; Koga, J. K.; Faenov, A. Y.; Pikuz, T.*; Kiriyama, Hiromitsu; Okada, Hajime; Shimomura, Takuya; Nakai, Yoshiki; Tanoue, Manabu*; Sasao, Hajime; Wakai, Daisuke*; Matsuura, Hideki*; Kondo, Shuji; Kanazawa, Shuhei; Sugiyama, Akira; Daido, Hiroyuki; Bulanov, S. V.

In order to generate a stable high-quality electron beam, optical injection by collision of two laser pulses is proposed. We succeeded a monoenergetic 134 MeV electron beam generation by the optical injection in a head-on laser pulses configuration. The experiments were carried out by the perfect head-on collision, which has problems to the backward laser light toward the laser system and the extraction of the generated electron beam. The counter-crossing injection, which is a realistic setup for applications, by two sub-relativistic laser pulses collision with the colliding angle of 45 is demonstrated. The collision of two laser pulses generates a high-quality electron beam with high repeatability. The generated monoenergetic electron beam has 14.4 MeV of the peak energy, 10.6% of the energy spread, 21.8 pC of the charge, 1.6 mm mrad of the normalized emittance, and 47.4% of the repeatability.