Lawrence Livermore National Laboratory

The Advanced Photon Technologies (APT) program investigates and develops cutting-edge photon technologies that enable both scientific advancement and new commercial applications. The program designs, models, develops, tests, and commissions next-generation laser technology and executes experiments to verify and validate advanced laser concepts relevant to fusion energy drivers, plasma physics, condensed-matter physics, laser propagation, and laser-matter interactions.

Key elements in the APT program are the research and development of advanced solid-state laser technology, ultrafast solid-state lasers, high-peak-power lasers, high-average-power lasers, and high-energy, high-intensity short-pulse lasers. APT is actively researching:

  • Diode-pumped solid-state lasers
  • High-energy solid-state lasers
  • Short-pulse lasers
  • Optical parametric short-pulse amplifiers
  • Chirped-pulse amplification
  • High-power fiber lasers
  • Solid-state laser materials science
  • Frequency conversion and non-linear optics
  • Short-pulse laser diagnostics, and
  • Advanced laser concepts.

Opening New Research Vistas

APT delivered the High Repetition Rate Advanced Petawatt Laser System (HAPLS) to the Extreme Light Infrastructure Beamlines Facility in the Czech Republic in June, 2017. HAPLS, now installed in the ELI Beamlines facility and called L3-HAPLS, is the world’s highest-average-power petawatt (quadrillion-watt) laser system.

HAPLS is capable of energetic femtosecond (quadrillionth of a second) laser pulses reaching a peak power exceeding one petawatt at a repetition rate of 10 times per second. The laser is able to deliver unprecedented intensities on target—up to 1023 watts per square centimeter. Achieving this intensity opens up entirely new areas of laser–matter investigation, enables new applications of laser-driven x rays and particles, and for the first time allows researchers to study laser interactions with the sea of virtual particles that comprise a vacuum.

L3-HAPLS will have a wide range of uses, supporting both basic and applied research. By focusing petawatt peak power pulses at high intensity on a target, the system will generate secondary sources such as electromagnetic radiation or accelerate charged particles, enabling unparalleled access to a variety of research areas, including time-resolved proton and x-ray radiography, laboratory astrophysics, and other basic science and medical applications such as for cancer treatments—in addition to industrial applications such as nondestructive evaluation of materials and laser inertial fusion energy.

Leading the L3-HAPLS project allowed LLNL to draw on its decades of pioneering laser research and development and apply that expertise to advance new laser concepts important for its missions.

Next-Generation Gratings

The APT program has also designed a new generation of compressor gratings that could boost the performance of the world’s ultrafast high-power laser systems by as much as 20 percent. The new gratings also can support hundreds of kilowatts of average power—an increase of about 10,000 times compared to common industrial technologies.

For LLNL’s HAPLS and Advanced Radiographic Capability (ARC) projects, APT researchers developed gold-coated dielectric ridge (GCDR) gratings for use in high-average-power lasers. The GCDR gratings demonstrated improved efficiency and uniformity compared to previous high-average-power-class gratings consisting of gold-coated etched substrates. The GCDR gratings, along with an LLNL-developed active cooling system, ultra-low thermal expansion substrates, and a variety of other innovations enabled HAPLS to meet its design requirements.

Engineer Inspects ARC Diffraction GratingEngineer JB McLeod inspects one of the high-efficiency diffraction gratings installed in NIF’s Advanced Radiographic Capability (ARC) compressor vessel. ARC’s one-meter-wide multilayer dielectric gratings were specially developed at LLNL to withstand the record levels of energy generated by NIF’s lasers.

The new gratings represent the culmination of two Laboratory Directed Research and Development (LDRD) projects and LLNL’s years of experience in developing high-energy laser systems. The Laboratory has also been a decades-long leader in the design and fabrication of the world’s largest diffraction gratings, such as the gold gratings used to produce 500-joule petawatt pulses on the Nova laser, the world’s first petawatt laser, in the 1990s.

More Information

“Superfast, Superpowerful Lasers Are About to Revolutionize Physics,” Scientific American, March 19, 2020

“New Gratings Promise 20 Percent Performance Boost for Ultrafast Lasers,” NIF & Photon Science News, October 15, 2019

“Nobelist’s Invention Helped Spark LLNL’s Short-pulse Laser Breakthroughs,” NIF & Photon Science News, October, 2018

“LLNL-Developed Petawatt Laser System Ready for Experiments,” NIF & Photon Science News, July, 2018

“LLNL-Developed Petawatt Laser Installed at ELI Beamlines,” NIF & Photon Science News, January, 2018

“Advanced Laser Promises Exciting Applications,” Science & Technology Review, July/August, 2017

“A Powerful Petawatt Laser for Experimental Science,” Science & Technology Review, July/August, 2017

“Powerful Laser System Improves Experimental Capabilities,” Science & Technology Review, January, 2016

“Highest-power Laser Diode Arrays Commissioned,” NIF & Photon Science News, March, 2015

“Lighting a New Era of Scientific Discovery,” Science & Technology Review, January-February, 2014

Next up: Advanced Laser Systems