10 PW L4-ATON LASER SYSTEM INSTALLED AT ELI-BEAMLINES
The 10 PW laser system designed by National Energetics for the Extreme Light Infrastructure Beamlines facility (ELI-Beamlines) in the Czech Republic has passed a major developmental milestone. The system has been successfully installed at the ELI-Beamlines facility, and both of its output modes have achieved > 1 kJ operation.
The L4-Aton laser, named for the figure of the Sun Disk in Egyptian mythology, is a dual-beamline system, allowing operation in either a short pulse (<150 femtosecond) or nanosecond long pulse mode. In short pulse mode, the laser delivers 10 PW with 1.5 kJ at 150 fs, and in long pulse mode, a narrow-band, nanosecond, temporally-shaped pulse of up to nearly 2 kJ.
The broadband short pulse front end utilizes Optical Parametric Chirped Pulse Amplification (OPCPA), followed by successive stages of direct amplification in two types of laser glass discs, which utilize novel face‑cooling techniques that allow an augmented system repetition rate of 1 shot per minute. At the National Energetics Austin Facility, short pulse front end amplification exceeded a kilojoule, using less than 75% of the available OPCPA seed energy and 6 out of 7 and 9 out of 10 amplifier modules in each disc amplifier chain, respectively. When compression is achieved at ELI, ATON will be the first rep-rated ultrafast-pulse kilojoule laser in the world.
The long pulse front end uses the same final amplifier chain as the short pulse font end, seeding these glass disc amplifiers with up to 30 J of temporally-shaped, nanosecond-duration narrow-band pulses. After installation at the ELI-Beamlines facility, National Energetics demonstrated amplification to 1.2 kJ using only 6 J of the available seed energy, with lamp voltages at 82% of their maximum rating.
National Energetics face-cooled disk amplifiers are modular in nature, allowing addition of modules as necessary to meet the desired energy requirements. These modules fire successfully at a rep rate of once per minute, with demonstrated focus ability of the amplified beam at a repetition rate of once per 5 minutes. Energy stability is +- 5% of the desired output.
This CAD layout shows the major components of the system. The broad-band front end consists of a femtosecond oscillator and components that select a single seed pulse from the oscillator, amplify it with picosecond OPCPA, enhance its contrast then stretch it for further amplification. The second stage provides the majority of the system gain through a series of nanosecond OPCPA amplifiers, boosting the energy from 0.1 mJ to > 4 J. The seed pulse is then injected into two different types of doped disc amplifiers. The first uses silicate glass while the second amplifier uses phosphate glass. The two laser glass materials have different amplification center wavelengths, and together, amplify the full bandwidth of the seed pulse to generate sub-150 fs pulses.
“The combination of high energy and peak power make this laser unique in the world,” said ELI-Beamlines Chief Laser Scientist Bedrich Rus. “In combination with the other laser systems within ELI-Beamlines, we will offer our users capabilities that will allow major advances in basic science and medicine.”
The program now moves on into its final phase, which includes transportation and compression of the chirped broad-band amplified beamline to its target of 150 fs. Installation of the compressor chamber, shown above at the Streicher manufacturing facility, is set to begin in Summer of 2019.
National Energetics Installation team at the ELI facility in Dolni Brezany, CZ. Left-right, Mike Donovan, Sandi Bruce, Gavin Friedman, Gilles Cheriaux, Mathew Tyrrell, Christopher Jaska, Ted Borger, Eric Beutlich, Erhard Gaul, Elliott Cheriaux, Andreas Gaul.
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