The Extreme Light Infrastructure (ELI) is part of the European plan to build the next generation of large research facilities selected by the European Strategy Forum on Research Infrastructures (ESFRI). ELI is the world's first infrastructure capable of investigating light–matter interactions at the highest intensity, in the so-called ultra-relativistic range.
The ELI Attosecond Light Pulse Source (ELI ALPS) is a unique attosecond facility that provides ultrashort light pulses from the THz to the X-ray frequency range with a high repetition rate for researchers and end users.