Lawrence Livermore National Laboratory

William H. Goldstein

William H. Goldstein

Director of Lawrence Livermore National Laboratory

A Powerful Petawatt Laser for Experimental Science

FOR more than 40 years, Lawrence Livermore researchers have been developing cutting-edge laser systems, technologies, and optics. Today, the Laboratory is known internationally for designing, building, and reliably operating complex lasers that are aimed at advancing high-energy-density science, national security, inertial confinement fusion, and U.S. industrial competitiveness. Many of these systems have broken world records in laser energy, power, and brightness.

Recognizing Livermore’s preeminence in high-power laser technology, in 2013, the European scientific community engaged with the Laboratory to design and construct the world’s first laser capable of generating 30-femtosecond (30 quadrillionths of a second) pulses with peak power of more than 1 petawatt (1 quadrillion watts, or 1015 watts) 10 times per second. Called the High-Repetition-Rate Advanced Petawatt Laser System (HAPLS), this machine will be a major resource for the European Union’s Extreme Light Infrastructure (ELI) Beamlines facility, located in the Czech Republic.

As the feature article, Advanced Laser Promises Exciting Applications, describes, an exceptionally dedicated team of Livermore physicists, engineers, materials scientists, computer scientists, and technicians worked with their colleagues from ELI Beamlines to design, develop, and build HAPLS. In only three years—an extremely short time considering the technology advances that were required—HAPLS went from concept to a fully integrated system, becoming the world’s highest repetition-rate petawatt laser. To meet its unique design goals, the HAPLS team incorporated Livermore advances in optics, integrated control systems, modeling and simulation, materials science, thermal management, pulse compressor gratings, systems engineering, and project management. Remarkably, this extraordinary machine can be operated by only two people, as the team demonstrated last year.

The Livermore–Czech partnership was made possible through an agreement for commercializing technology (ACT)—a new technology transfer mechanism piloted by the Department of Energy (DOE). This mechanism was conceived to help national laboratories form research partnerships using contractual terms better aligned with industry practice. Under an ACT, national laboratory contractors may take on financial risk that the U.S. government cannot assume. The Board of Governors for Lawrence Livermore National Security, LLC, which manages the Laboratory for DOE’s National Nuclear Security Administration, elected to enter into the largest ACT agreement within the DOE national laboratory family to make HAPLS a reality. In agreeing to a fixed-price contract at its own financial risk, the board expressed confidence in the team’s ability to complete the assignment on time and on budget and meet all technical milestones. The board also recognized the project’s importance in maintaining the Laboratory’s preeminence in high-average-power laser expertise.

HAPLS represents a new generation of high-energy and high-peak-power laser systems. HAPLS’s designed firing rate—10 times a second—is a major advance over current petawatt systems, which can fire a maximum of only once per second because of their reliance on traditional flashlamps to pump their amplifiers. To overcome that serious limitation, HAPLS features the world’s highest peak-power laser diode arrays. These arrays, developed through a Livermore partnership with the U.S. firm Lasertel, Inc., earned an R&D 100 Award as one of the top technology breakthroughs of 2015. HAPLS’s unprecedented repetition rate will improve the signal-to-noise ratio in experiments and thereby enable groundbreaking research in basic physics, materials science, biomedicine, laboratory astrophysics, and industrial processes.

HAPLS passed its final commissioning milestone at Lawrence Livermore in December 2016, some 20 years after Livermore’s Nova Petawatt laser became the first system to achieve peak power greater than 1015 watts. After completing its qualification testing, HAPLS was disassembled and shipped to the ELI Beamlines facility in June. This fall, Livermore staff will be on hand to install and commission the system in the Czech Republic. I look forward to the results achieved from the first experiments conducted on HAPLS, which are expected to begin in 2018. In the meantime, Lawrence Livermore will continue to seek collaborations that leverage our expertise and technology. Such collaborations provide the Laboratory with opportunities to carry on its tradition of more than four decades pushing the frontiers of science.