First observation of quasi-monoenergetic electron bunches driven out of ultra-thin diamond-like carbon (DLC) foils

Electrons have been accelerated from ultra-thin diamond-like carbon (DLC) foils by an ultrahigh-intensity laser pulse. A distinct quasi-monoenergetic electron spectrum peaked at 30 MeV is observed at a target thickness as thin as 5 nm which is in contrast to the observations of wide spectral distributions for thicker targets. At the same time, a substantial drop in laser-accelerated ion energies is found. The experimental findings give first indication that relativistic electron sheets can be generated from ultra-thin foils which in future may be used to generate brilliant X-ray beams by the coherent reflection of a second laser.