Laser-driven electron acceleration in gas media  provides extreme accelerating fields around 100 GV/m, however, using vacuum should offer even multi-TV/m values. These fields are much beyond that of conventional RF devices. Furthermore, the electron bunches have durations in the few-femtosecond regime, which is also much shorter than from conventional facilities.
A novel approach for the acceleration, that we termed relativistic nanophotonics, utilizes solid density nanoplasmas irradiated with sub-5-fs ultra-relativistic laser pulses . The target emits electrons in intensity- and target size-dependent directions. The electrons are in the 5-10 MeV energy range and possess a clear dependence in propagation direction also on the waveform of the laser (carrier-envelope phase). An average experimental accelerating field beyond 1 TV/m is evaluated. Numerical investigations  indicate a two-step process behind the interaction. First a nanophotonics step emits electron pulses and accelerates them to a certain energy, while a second vacuum laser acceleration step further accelerates them and determines their final propagation direction. The simulations predict isolated electron pulses with a duration of about 300 attosecond and a peak accelerating field up to 10 TV/m.
These results form the basis of high-energy micro- to nanoaccelerators, record-breaking accelerating electric fields strengths, and isolated attosecond electron bunches. These accelerators are unique candidates as a source of energetic X-ray radiation with attosecond pulse duration.
 E. Esarey et al., Rev. Mod. Phys. 81, 1229 (2009).
 D. E. Rivas et al., Sci. Rep. 7, 5224 (2017).
 L. Di Lucchio et al., Phys. Rev. ST Accel. Beams 18, 023402 (2015).
|Working group||Invited plenary talk|