In the case of the L1 system, the team has designed and developed kHz repetition-rate laser amplifiers based on the so-called thin-disk technology, providing more than 100 mJ of energy in the pulse in a beam of excellent spatial quality. The diode-pumped thin-disk laser heads were delivered by a commercial company. For the L2 system, developed in partnership with the Rutherford Appleton Laboratory (U.K.), the ELI-Beamlines team works on technologies for Helium-cooled multislab amplifiers. These include advanced methods of cryogenic He cooling based on the Brayton cycle, new laser active materials based on Yb:doped YAG monocrystals, new techniques of temporal shaping of the laser pulse, advanced repetition-rate laser diagnostics, and control and timing systems.
The L1 laser is being developed in house by the ELI-Beamlines laser team. The laser system is designed to generate <20 fs pulses with energy exceeding 100 mJ per pulse at a high repetition rate (1 kHz). The concept of the laser is based entirely on amplification of frequency chirped picosecond pulses in an optical parametric chirped pulse amplification (OPCPA) chain consisting of a total of seven amplifiers. The OPCPA amplifier stages are pumped by precisely synchronized picosecond pulses generated by state-of-the-art thin-disk-based Yb:YAG laser systems.
The L2 beam line is a laser system designed to generate ultrashort laser pulses with peak power reaching 1 PW (1 petawatt = 1,000,000,000,000,000 watts). The laser will be able to operate at a high repetition rate of 10Hz due to the full utilization of new technologies such as laser diode pumping and cryogenic cooling of the laser material. The main amplifiers are based entirely on optical parametric chirped pulse amlification (OPCPA), allowing for extremely short pulses with durations below 15 fs to be generated.