A high stability electron bunch is generated by laser wakefield acceleration with the help of a colliding laser pulse. The wakefield is generated by a laser pulse; the second laser pulse collides with the first pulse at 180° and at 135° realizing optical injection of an electron bunch. The electron bunch has high stability and high reproducibility compared with single pulse electron generation. In the case of 180° collision, special measures have been taken to prevent damage. In the case of 135° collision, since the second pulse is countercrossing, it cannot damage the laser system.

• Received 31 October 2008

DOI:https://doi.org/10.1103/PhysRevLett.103.194803