Jupiter Laser Facility

Overview

The Jupiter Laser Facility (JLF) 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. External user access to JLF is obtained 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. Historically, one of the lasers of JLF (Janus) has led to pioneering achievements for the LLNL inertial confinement fusion and x-ray laser programs in the 1970s and 1980s, notably to demonstrate for the first time the thermonuclear reaction in laser-imploded deuterium–tritium fuel capsules. Many platforms, techniques and diagnostics used at the National Ignition Facility today have been developed through initial experiments at JLF. The Facility’s vision is to be the preeminent hands-on facility for addressing unique challenges and questions in high energy density and laser science within the national and international ecosystem. The facility fulfills this vision by partnering with the broad scientific community to develop new experiments, by developing laser-driven sources, by testing new laser, optical, target and diagnostic capabilities, and by training the next generation of researchers in high energy density and fusion sciences.

Janus and Titan

After more than 10 years of operation, Janus and Titan have undergone extensive refurbishment, with return-to-full-operations at the end of 2023. Janus and Titan refer to the target areas. They make use of three high-energy beamlines, two long pulse beamlines and one short pulse beamline. Titan and Janus have a dedicated short and long pulse beamline, respectively, and they can both also use one shared long pulse beamline. All three beams employ glass amplifiers and have a 30-minute duty cycle. All experiments are hands-on for users.

Titan has a dedicated ps beam, 0.7 to 200 ps, with energies currently up to 250 J (depending on pulse duration) at fundamental (1053 nm) into a 2-m-diam chamber; the option of full-aperture conversion to 2ω (up to 50 J) is also possible. (Beam energy is limited until new pulse-compression gratings have been installed, planned for late 2024.) The Titan short-pulse beam uses an f/3 final optic, but f/10 can be arranged. The focal spot is < 10 μm with a strehl > 0.5. Using a beam-splitter inside the chamber, the beam can be split into two differently pointed beams. A second, long-pulse, beam – 0.5-20 ns with energy up to 850 kJ (1ω) or 500 J (2ω) – can be simultaneously transported to the chamber with arbitrary timing between the beams. A mJ-level probe beam is also available.

Janus has a dedicated long pulse beam with the second long-pulse beam shared with the Titan target area. Both beams are 0.5-20 ns with energy up to 850 kJ (1ω) or 500 J (2ω) and have largely arbitrary pulse-shaping. Both beams have polarization control and can be detuned by ~ 1 nm in wavelength. The minimum spot size is < 20 μm with a strehl > 0.5. Phase plates are available for 200, 400, 600, 100, and 2000-μm spot sizes. A dual-echelon VISAR system and streaked optical pyrometry are standard diagnostics in Janus. A mJ-class Ti:Sapphire probe is also available.

COMET

COMET is a 5-minute-rep-rate laser with either short-pulse (0.5-50 ps) or long-pulse (0.75)  configuration and energy up to 10 J (1053 nm). Conversion to 2ω (527 nm) is possible, with a conversion efficiency of about 50%. Short and long pulses can be used simultaneously (with a total maximum energy of 10 J at 1ω), and a probe is available (see characteristics) COMET has its own cylindrical chamber. Following some brief training, users are permitted to charge and fire COMET.

More information can be found at jlf.llnl.gov.