The L4 Aton 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 | <550×550 mm |
L4 current parameters
Short Pulse beamline (CPA regime)
| Output pulse energy | >1,500 J |
| Pulse duration (CPA regime) | ~150 fs FWHM |
| Central wavelength | 1060 nm |
| Maximum Repetition rate | 1 shot per minute |
| Front-End Energy / repetition rate | 4.8 J / 5 Hz |
| Pump laser technology | flashlamp-pumped Nd:glass amplifiers |
| Output laser pulse energy RMS stability | better than 2.5% RMS |
| Output laser beam RMS pointing stability | <8 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 | square super-Gaussian |
| Clear Aperture of compressed beam | 650×650 mm |
L4 current parameters
Long Pulse beamline (Non-CPA regime)
| Design Output pulse energy | >1,900 J |
| Pulse duration (Non-CPA regime) | 150 ps to 10ns (pulse shaping with 150ps step and high double pulse contrast) |
| Central wavelength | 1053 nm |
| Maximum Repetition rate | 1 shot per minute |
| Front-End Energy / repetition rate | 30 J / 1 shot per minute |
| Pump laser technology | flashlamp-pumped Nd:glass amplifiers |
| Output laser pulse energy RMS stability | better than 2.5% RMS |
| Output laser beam RMS pointing stability | <8 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 | square super-Gaussian |
| Clear Aperture of output beam | 323×323 mm |
| Auxiliary CPA Beam Energy / Pulse Duration | 100 J / 150 fs |
Delivery of the system
The delivery of the L4 Aton 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.
References: Bedrich Rus, bedrich.rus@eli-beams.eu
