L4: 10 PW, 2 kJ Beam Line

Eli Beamlines L4 Laser

L4: 10 PW, 2 kJ Beam Line

The L4 beam line is designed to generate an extremely high and unprecedented peak power of 10 PW (Petawatt) during pulse duration of about 130 fs. The uncompressed energy can reach almost 2 kJ with a shot rate of 1/min, which is a major step in the field of kJ-class lasers. The architecture is based on direct compression of a broadband beam amplified by a combination of different Nd:glass slabs.

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)

Repetition rate

1 shot per minute

Peak power

10 PW

Pump laser technology

flashlamp-pumped Nd:glass amplifiers

Output laser pulse energy RMS stability 

better than 10% rms

Output laser beam RMS pointing stability

<10 µrad

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 format 

rectangular superGaussian

Beam size of compressed beam

<550x550 mm

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 daniel.kramer@eli-beams.eu

Related pages

Research / Laser Technology / Petawatt Lasers

ELI Beamlines' laser team is developing and co-developing, in partnership with major laser technology suppliers of the project, a number of essential systems for Petawatt (PW) and 10-PW lasers.