Fraunhofer Institute for Laser Technology ILT
Fraunhofer Institute for Laser Technology ILT
© Fraunhofer ILT, Aachen

© Fraunhofer ILT, Aachen

Fusion

Today, there are two main approaches being considered for commercial power plants: magnetic fusion and laser fusion. In both cases, usable energy is released through the correct interaction of density, temperature, and confinement time of an ignited plasma. An important physical milestone has been reached in laser fusion. The Lawrence Livermore National Laboratory in California has repeatedly demonstrated at the National Ignition Facility (NIF) that a deuterium-tritium plasma can be ignited by laser inertial confinement fusion (ICF), triggering a self-sustaining fusion process. An extremely short laser pulse causes a fuel pellet measuring a few millimeters in diameter to implode, generating the required density and temperatures. Since December 2022, this so-called "ignition" regime has been achieved repeatedly. However, the NIF is a research facility. It proves the physical feasibility of laser fusion but does not replace a power plant. The next crucial step is to further develop the necessary technologies to enable stable, efficient, and industrially viable fusion operation.

A safe, virtually inexhaustible source of energy for the future

Life on Earth is based on solar radiation. Its energy is fed by the fusion of hydrogen into helium, a process that has been going on for billions of years. During fusion, light atomic nuclei merge to form a heavier nucleus, releasing enormous amounts of energy. This inexhaustible, climate-neutral, and base-load-capable energy source is also set to become usable on Earth in the future. Research institutions, industrial companies, and start-ups around the world are working intensively on concepts and technological building blocks for nuclear fusion power plants.

The fusion of the hydrogen isotopes deuterium and tritium into helium is considered particularly promising. Several conditions must be met for this reaction to take place. These include temperatures of around 150 million degrees Celsius. Only under these extreme conditions do the positively charged nuclei overcome their mutual repulsion, known as the Coulomb wall, and approach each other to within about one femtometer. At this distance, the strong nuclear force causes deuterium and tritium to fuse into a helium nucleus. This also produces a free neutron.

The mass of the initial isotopes is greater than the sum of the masses of the resulting helium nucleus and the released neutron. The resulting mass defect is converted into binding energy in accordance with Einstein's equivalence of mass and energy. Each fusion reaction releases 17.6 megaelectron volts (MeV), 14.1 MeV of which is in the form of the kinetic energy of the neutron. Extrapolated, this corresponds to around 92,000 kilowatt hours of energy per gram of deuterium-tritium mixture.

To put this into perspective: 1 kg of deuterium-tritium mixture could theoretically yield as much energy as around 10 million liters of diesel or around 20,000 tons of lignite.

Expertise in laser fusion and magnetic fusion

Several Fraunhofer Institutes are already jointly researching, developing, and supplying key technology components for laser fusion and magnetic fusion. This close cooperation within the Fraunhofer Society is complemented by international collaborations, including with Lawrence Livermore National Laboratory. In addition, we are driving forward technological development as part of publicly funded collaborative research together with partners from industry and science.

Fraunhofer ILT contributes its laser technology expertise to both fusion approaches. In the field of laser fusion, the focus is on the development of high-energy lasers, heavy-duty optics, and sustainable photonic processes for manufacturing key power plant components.

© Fraunhofer ILT, Aachen.

In addition, we are researching laser-based secondary sources, for example for the generation of X-ray and extreme ultraviolet radiation, and for the development of neutron sources. These are needed to test materials for fusion power plants under realistic conditions. We also use laser-based additive manufacturing for the development of new target manufacturing processes.

For magnetic fusion, the focus is particularly on laser-based manufacturing and processing methods. Lasers are used here for structuring surfaces, joining and cutting, and in the additive manufacturing of highly specialized power plant components.

The path from research to fusion power plants

A look at the National Ignition Facility in California shows the technological challenges facing laser fusion today. The NIF laser system covers an area roughly the size of three football fields and bundles 192 beam paths. Laser light is amplified in large solid-state amplifier plates and then formed into pulses lasting around ten nanoseconds. All pulses strike a tiny target simultaneously, together reaching an energy of 2.05 megajoules. 

© Fraunhofer ILT, Aachen.

The NIF facility is deliberately designed as a research infrastructure and demonstrates the fundamental feasibility of laser fusion. However, the underlying technologies need to be significantly further developed for later power plant operation. These include a significantly higher overall efficiency of the laser systems, a sharp increase in the repetition rate of individual shots towards continuous operation, and cost reduction and scaling for key components such as optics, laser diodes, and targets. The goal is to derive industrial systems from today's research setup that make laser fusion usable as a clean and sustainable energy source.

 

© Fraunhofer ILT, Aachen, Germany.

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  • Laser fusion – a promising market at LASER 2025

    Press Release / June 11, 2025

    Prof. Constantin Haefner, Executive Board Member for Research and Transfer at the Fraunhofer-Gesellschaft, will open the discussion with his keynote speech on the application panel “Laser Fusion: Energizing Photonics Industry”.
    © Fraunhofer ILT, Aachen, Germany / Andreas Steindl.

    Laser-based inertial confinement fusion is a market that holds strategic value for the photonics industry. Its feasibility has already been demonstrated. In Germany, consortia from industry and research are forming to tap this climate-neutral and intrinsically safe energy source and create powerful supply chains for it. The state is providing over one billion euros to develop basic technologies for fusion power plants. Current approaches have great potential for innovation beyond fusion. Key players will meet at LASER 2025 for the application panel "Laser Fusion: Energizing photonics Industry". Led by the Fraunhofer ILT, it will shed light on the market potential and opportunities of fusion.

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  • Joint project PriFUSIO explores technological paths to commercialize inertial fusion / 2024

    New foundation for laser fusion research

    Press Release / April 16, 2024

    Fusion energy: clean and virtually inexhaustible energy source of the future
    © Shutterstock.

    Boost for Inertial Fusion Energy (IFE) in Germany: The PriFUSIO research project aims to systematically develop key technologies for climate-neutral fusion power plants of the future. The consortium, led by the ILT in Aachen, brings together fusion start-ups, medium-sized companies, large corporations, the Laser Zentrum Hannover, and the Fraunhofer Institutes IOF in Jena and ILT in Aachen, creating a diverse collaboration of industry and public research institutions. The project will focus on principles for targeted component development and explore practical photonic approaches for the commercial utilization of laser-driven IFE. The Federal Ministry of Education and Research has allocated 18 million euros for the project over the next three years.

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  • Boost for laser-based Inertial Fusion as energy source of the future

    Press Release / December 07, 2023

    Fusion Energy.
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    In a historic breakthrough in December 2022, the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL), California, USA, successfully achieved a self-sustaining burning plasma, providing compelling evidence for the viability of Inertial Fusion Energy (IFE) as a crucial addition to carbon-free, safe, and clean energy sources. This remarkable accomplishment has led to the allocation of $16 million in funding by the US Department of Energy to establish the IFE Science & Technology Accelerated Research for Fusion Innovation & Reactor Engineering (STARFIRE) Hub. Fraunhofer ILT proudly contributes as part of the multi-institutional team led by Lawrence Livermore National Laboratory.

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  • Historical breakthrough in fusion research: Lasers have ignited fusion!

    Press Release / December 13, 2022

    Fusion energy.
    © shutterstock.

    Lasers have ignited a mini star on earth, laying the foundation for a clean energy source of the future: A historical breakthrough in inertial confinement fusion research at the National Ignition Facility at Lawrence Livermore National Lab and a defining moment for Photonics! One of the most promising applications of laser technology, the realization of laser-driven fusion, has achieved a historical breakthrough. As announced by Lawrence Livermore National Laboratory (LLNL, California, USA) in its press release dated December 13, 2022, American scientists at the National Ignition Facility (NIF) were able to release a fusion energy of 3.15 megajoules (MJ) from a pellet filled with the hydrogen isotopes deuterium and tritium. This is equivalent to 154 percent of the expended energy equivalent to 2.05 MJ of the laser pulse that triggered the explosion. This net energy gain represents the first internationally long-awaited breakthrough in fusion research. These results will provide unprecedented capability to support US Department of Energy’s High Energy Density Physics mission and established the physics platform to generate an efficient energy source comparable to the sun, making it a viable long-term complement to renewable energy.

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