  Laser-plasma accelerators produce electric fields of the order of 100 GV/m,
more than 1000 times larger than radio-frequency accelerators. Thanks to this
unique field strength, they appear as a promising path to generate electron
beams beyond the TeV, for high-energy physics. Yet, large electric fields are
of little benefit if they are not maintained over a long distance. It is
therefore of the utmost importance to guide the ultra-intense laser pulse that
drives the accelerator. Reaching very high energies is equally useless if the
properties of the electron beam change completely shot to shot. While present
state-of-the-art laser-plasma accelerators can already separately address
guiding and control challenges by tweaking the plasma structures, the
production of beams combining high quality and high energy is yet to be
demonstrated. Here we use a new approach for guiding the laser, and combined it
with a controlled injection technique to demonstrate the reliable and efficient
acceleration of high-quality electron beams up to 1.1 GeV, from a 50 TW-class
laser.
