Diode laser pump sources for future fusion power plants

Diode laser pump sources for future fusion power plants Future climate-neutral fusion power plants need vast numbers of cheaper, improved high-power laser diodes. Germany’s BMFTR-funded DioHELIOS project boosts semiconductor laser power and efficiency while developing automated mass-production approaches. In December 2022, researchers succeeded for the first time in generating excessive energy from a controlled nuclear fusion reaction.1 Since then, the US National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory in California has achieved fusion multiple times beyond scientific break-even with up to fourfold net gain with respect to the optical input energy of their lasers.2 The demonstration of laser-ignited inertial confinement fusion has triggered a new dynamic in fusion research worldwide. This is because fusion not only decouples energy production from the carbon cycle by emitting no greenhouse gases but is also based on an almost unlimited supply of fuel and could, in theory, be operated 24/7 at maximum safety. Germany recognised the new dynamic early on and set up the ‘Fusion 2040’ funding programme in 2024.3. With its partners ams-OSRAM, the Ferdinand-Braun-Institut (FBH), the Fraunhofer Institute for Laser Technology ILT, Jenoptik, LASERLINE, and TRUMPF, the ongoing project ‘DioHELIOS’ (Diode Laser Pump Sources for High-Energy Lasers in Fusion Power Plants) has brought together a broad consortium from the photonics industry and research to advance a key component for fusion power plants of the future: high-power diode laser modules. These are needed as pump sources for the high-energy lasers that compress plasma from hydrogen isotopes to hundreds of billions of atmospheres and ignite it at temperatures ten times hotter than inside the Sun. At NIF, this task is assigned to the world’s largest and highest-energy laser facility. On an area the size of three football fields, 192 beam paths generate over two megajoules of ultraviolet (UV) laser energy per pulse. Conventional flash lamps are used as the pump source – comparatively cheap, but inefficient and unable to operate at the repetition rate required for a power plant, in contrast to laser diodes.