The objective of this Research Activity is to deliver the laser system, the principal instrument and the backbone of the whole ELI facility. Tasks to be carried out will include scientific and engineering design of the laser system and of its individual components and subsystems, development of selected components, assembling, testing and optimization of individual sections of the laser. Essential element underpinning all of these efforts will be the international cooperation. Upon completion of the laser system and its commissioning for users, this Activity will continue the development of particular subsystems, especially the repetition rate Beamlines and the high-intensity multi-10-PW section.

“Lasers” is the largest research activity of this project. It will exploit work carried out by the international consortium working within the ELI-Preparatory Phase (www.eli-laser.eu), especially within the ELI-PP Work Package 7A (Lasers).

The baseline design of the ELI laser system features multipurpose mission of this facility in fundamental and applied research, as well as versatility of its operation for user research.

Research Activity Description

The laser systems in the Czech Republic will consist of the front end, booster amplifiers, repetition rate Beamlines, and high-intensity (nominally 10-PW) test blocks. The laser front end will deliver 5-fs pulses with high contrast, at a repetition rate 1 kHz, and will feed pulses into amplifiers and Beamlines of the laser chain.

The booster repetition-rate amplifiers will be based on the PFS (Petawatt Field Synthesizer) technique and will be pumped by thin-disk diode-pumped solid state lasers (DPSSL). Two types of boosters will be employed, running at 1 kHz and 100 Hz respectively. The repetition rate Beamlines will run at 10 Hz and will deliver 10 J and 50 J of energy in compressed pulses with nominal duration of 10-15 fs.

The designed system involves two 10-J and two 50-J Beamlines based on the OPCPA technique and using multi-slab cryogenic DPSSL units as a pump. Given a fairly tight schedule for development of the DPSSL pump units for 50-J Beamlines, a fallback solution are Ti:Sapphire amplifiers using flashlamp pump lasers; the repetition rate provided by these systems would however be 0.1 Hz. The peak power delivered by the Beamlines will be typically of the order of PW. The pulse length at the output of these systems will be adjustable for the needs of research of the electron and proton acceleration.

The designed ELI facility will involve two blocks providing the peak power of 10-PW. These blocks will provide energy of 200-300 J in 20-30 fs pulses at the repetition rate of up to 0.1 Hz. These blocks will serve to test and prototype technologies for the ELI high-intensity facility that is intended to deliver 200 PW peak power.

Results and outputs of this Research Activity will be exploited by all research projects and by all users of the ELI facility, as all projects carried out at this facility will be using the laser system as a principal research tool. In broader context, the Research Activity will help establishing a major laser research facility in the world, and will stimulate development of new technologies by laser, optical, vacuum, electronic and other industry.

Main outcomes of the Research Activity

The main outcome of this Research Activity will be the implementation of the laser system that will be the core of the whole ELI infrastructure and that will constitute a major world-class laser facility. The laser system will exploit state-of-the-art and industrially highly relevant technologies, most notably the diode-pumped solid state lasers (DPSSL) that will be used in the repetition-rate booster amplifiers and in the repetition-rate Beamlines. Furthermore, the laser system will involve a test high-intensity section consisting of two 10-PW amplifiers and compressors. Among the outcomes will be demonstration of techniques for compression and of coherent superposition of multi-10-PW pulses.