Jupiter Laser Facility

Lawrence Livermore National Laboratory
Availability in Run 2

Titan and Janus will be down all of 2020 – return to user operations is scheduled for July 2021.

COMET will be available for Run 2 March through November 2020, for roughly two 4-week experiments.

The Jupiter Laser Facility (JLF), built in 2006 and located at Lawrence Livermore National Laboratory (LLNL), is an intermediate-scale, open laser facility dedicated to high-energy density science, with three operating laser systems and target areas: Titan, Janus, and COMET. JLF is the 5th highest energy laser in the US. In scale and operation, JLF is similar to lasers at the Central Laser Facility at Rutherford- Appleton Laboratory in the UK and the Laboratoire pour l’Utilisation des Lasers Intenses (LULI) located at École Polytechnique in France. Access to JLF is obtained through an annual call for proposals, and a fraction of the user time at JLF will be accessible through LaserNetUS. More than 100 Ph.D.’s have been granted that included thesis work at JLF, and the facility has been acknowledged in over 200 peer-reviewed publications.

Janus (long pulse)

Janus is a dual beam Nd:glass laser. Each beam is independent and capable of respectively 700 J and 500 J at 1.053 μm (200 J and 150 J at 527 nm) with pulse lengths from about 1 ns to 15 ns. (Each beam is capable of delivering 1 kJ. As part of an extensive refurbishment, each beam will be returned to full capability.) A variety of temporal pulse shapes are available, as well as 200-, 600- and 1000-µm phase plates. Janus fires approximately every 30 minutes.

The Janus target area has a cylindrical chamber (inside diameter of 857 mm, with a breadboard of 457 x 660 mm) that accepts multiple beam positions. A dual VISAR diagnostic (60 ns, 0.25 mJ, 527 nm) is available for operation by the users. A commercial short pulse laser (<100 fs, 800 nm, 20 mJ) is also available for use as a diagnostic for laser-plasma interaction experiments, interferometry, spectrometry, probing and white light generation for reflectometry.

Titan (short and long pulse)

Titan is a two-beam laser platform. The nanosecond, long-pulse, “East” beam is one of the Janus lasers - up to 700 J at 1.053 μm and 200 J at 527 nm with temporal shaping and available phase plates (200, 600 and 1000 µm). The 0.7 – 40 picosecond, short-pulse, “West” beam provides energies on target between 130 and 300 J, depending on pulse duration. With a minimum pulse width of a few μm, a range of intensities between 1019-1021 W/cm2 and a contrast of 10-5 are typical. The beams can be used together or independently. Titan has a repetition rate of two shots/hour, however if the Janus target area is using either the West or East beam, the repetition rate drops to 1 shot/hour.

The Titan target chamber is a large - 2.5 m - diameter vessel similar to the one available at SLAC/MEC. The target chamber has numerous ports on the sides, top and bottom, which can be fitted with windows, feedthrough ports, and target delivery systems. The ~ 25 cm diameter Titan short pulse can be focused down to 10 µm or 29 µm FWHM with an f/3 or f/10 off-axis parabola. An extension tube and separate chamber are installed for the f/10. In the f/3 configuration, the short pulse can be split into two beams. The long pulse comes through a rotating arm into the target chamber, through the port chosen by the users.

COMET

COMET is a stand-alone laser system with several beam configurations at 1.053 µm (some of which can be used at the same time), and has a four-minute cycle time between shots. It provides compressed pulses from 0.5 to 100 ps, pulses at 750 ps, or 2 ns, with energies on target up to 10 J. A 12-inch focal length off axis parabola is available to focus the 8.5 cm beam down to a 6 µm focal spot (FWHM)

Robert Cauble, cauble1@llnl.gov

COMET Short pulse

Parameter Value Unit Additional Information
Center Wavelength 1053 nm  
Pulse duration (I FWHM) 0.5 ps to 2000 ps long pulse
Max energy on target 10 J  
Shot energy stability   % unmeasured
Focal spot at target     Comet target chamber
F/number f/3.6    
intensity FWHM 6 μm  
Repetition Rate 15 hr-1  

Janus 1ω

Parameter Value Unit Additional Information
Center Wavelength 1053 nm  
Pulse duration (I FWHM) 0.5 ns to 15  Shaped pulse
Max energy on target 700 J 700
Shot energy stability 10 % r.m.s
Focal spot at target     In Titan target chamber
intensity FWHM 200 µm phase plate
  600 µm phase plate
  1000 µm phase plate
Repetition Rate 2 hr-1  

Janus 2ω

Parameter Value Unit Additional Information
Center Wavelength 527 nm  
Pulse duration (I FWHM) 0.5 ns to 15 ns, shaped
Max energy on target 200 J  
Shot energy stability 10 % r.m.s
Focal spot at target     In Titan target chamber
intensity FWHM 200 µm phase plate
  600 µm phase plate
  1000 µm phase plate
Repetition Rate 2 hr-1  

Titan

Parameter Value Unit Additional Information
Center Wavelength 1053 nm  
Pulse duration (I FWHM) 0.7 ps 40
Max energy on target 130 J 300
Shot energy stability 10 % r.m.s.
Focal spot at target      
F/number f/3   Split beam capability available for F/3
intensity FWHM 10 µm Measured at low laser power
Strehl ratio 0.5    
Energy containment   % within   µm radius
F/number f/10    
intensity FWHM 29 µm Measured at low laser power
Strehl ratio 0.5    
Energy containment 86 % within 28 µm radius
Pointing Stability   μrad (Typically within beam spot diameter)
Pre-pulse contrast      
ns scale     @   ns in progress
ps scale 10-5   @ 200 ps  
Repetition Rate 2 hr-1 or 1/hr if Janus uses west beam