The L4 system architecture
The L4 laser system can operate in two main modes:
- All the energy can be used to generate a power of 10 PW in a single beam. By-pass of the compressor is possible in order to use the chirped nanosecond (ns) beam directly.
- The main amplifier can deliver almost 2 kJ in a narrowband ns beam with variable temporal shaping seeded by a separate front end. At the same time, the broadband front end can seed the first main amplifier and thus provide a 200 J-class PW pulse.
The L4 laser chain is composed of a broadband ultrafast oscillator, picosecond OPCPA preamplifier, nanosecond OPCPA stages, and two main amplifier stages based on Nd:glass-gain media pumped by flashlamps. The resulting nanosecond pulses are compressed in a dielectric grating compressor.
L4 beam line design parameters (main beam)
Output pulse energy (main beam compressed)
>1,800 J in single aperture
Pulse duration (CPA regime)
<150 fs FWHM (adjustable to 100 ps)
Pulse duration (non-CPA regime)
0.5–5 ns (temporal shaping adjustable in 150 ps steps)
1 shot per minute
Pump laser technology
flashlamp-pumped Nd:glass amplifiers
Output laser pulse energy RMS stability
better than 10% rms
Output laser beam RMS pointing stability
Laser control system
Labview and EPICS
Output pulse external synchronization relative to the facility clock
<20 ps to RF clock with any delay relative to facility clock
Beam size of compressed beam
Delivery of the system
The delivery of the L4 laser system was contracted with the United States-Lithuanian consortium of National Energetics and Ekspla in September 2014.
The main subcontractors are Schott and Lawrence Livermore National Laboratory.
ELI-Beamlines staff is in charge of delivering for the following subsystems:
- Full diagnostics of the compressed 10 PW beam
- Design of the vacuum vessel for the 10 PW compressor
- Design and delivery of optomechanics for the 10 PW compressor
- Laser timing platform
- Contribution to the development of long pulse OPCPA amplifiers.
Daniel Kramer firstname.lastname@example.org