The International Cooperation on Next-gen Inertial Confinement Fusion Lasers (ICONIC-FL) project will combine the expertise of scientists at the Fraunhofer Institute for Laser Technology ILT (Fraunhofer ILT) and Lawrence Livermore National Laboratory (LLNL) to transition laser-ignited inertial fusion from the experimental stage to industrial application. In the newly launched initiative, the partners are collating their sophisticated laser simulation to develop high-energy lasers that can ignite a fusion reaction and run at maximum efficiency in 24/7 power plant operation. A production line was set up on site during the construction of the National Ignition Facility specifically for the manufacture of the laser glass plates. Courtesy of Lawrence Livermore National Laboratory (LLNL) via Fraunhofer Institute for Laser Technology ILT (Fraunhofer ILT). Since this undertaking requires precise and highly accurate predictions of laser performance, powerful computer simulations play a central role in the development of laser architecture. Since LLNL’s 2022 fusion breakthrough, the national lab has demonstrated that the physical principle of ignition works, several times and with increasing energy yield. A single ignition, however, won’t be sufficient for a future power plant; such a plant will require ~15 shots per second. This requires the use of efficient diode-pumped solid-state lasers (DPSSL) that can fire dozens of times per second. Fusion researchers at Fraunhofer ILT and Lawrence Livermore National Laboratory. Courtesy of LLNL via Fraunhofer ILT. To this end, LLNL and Fraunhofer ILT are pooling their complementary expertise to develop these lasers. While LLNL brings decades of experience in high-energy lasers technology, Fraunhofer ILT brings expertise in the development and industrial scaling of DPSSLs. “The transition from basic research to power plant development requires the rapid, robust development of rugged new laser systems rapidly,” said Tammy Ma, head of fusion research at LLNL. “Fraunhofer ILT's expertise in the industrial scaling of diode-pumped lasers is crucial for accelerating our IFE program.” The ICONIC-FL partners will simulate the amplification stages of high-energy lasers in as much detail as possible, thereby laying the foundation for a later design. The partners are focusing on the heart of the system — the laser amplifiers — as in these laser pulses, the photons transfer an energy of many millions of joules. Laser media used for this purpose consist of stacks of laser glass or crystal plates with an area of up to 40 cm × 40 cm and a thickness of a few millimeters and are cooled with transparent cooling media during operation. The amplifier plates are exposed to enormous thermal and optical stress. “[Twenty-four/seven] operation leads to heating, refraction effects, and aberrations that could distort the laser beam. Even the smallest, unpredictable effects are significant here and lead either to efficiency losses or direct damage to the optics,” said Johannes Weitenberg, project manager at Fraunhofer ILT. “We want to understand exactly what is happening in each individual plate so that we can then simulate complex plate stacks with precision.” By validating the designs in the simulation, the partners will simultaneously reduce technical and financial risks. With up to 400 beam paths in future power plant designs, even the smallest overlooked detail in the transition to series production can result in significant costs. “We are in the decisive decade for fusion energy. For inertial fusion to reach its full potential, we need to develop new laser architectures with uncompromising perfection,” said professor Constantin Häfner, executive vice president for research and transfer at the Fraunhofer-Gesellschaft.