Schott leads project SHARP to develop new mirrors for laser fusion

11 Mar 2025

Partners include LZH, Layertec, Asphericon, 3DMicromac, OptiXfab, Cutting Edge Coatings, Robeko, and Fraunhofers.

Laser-driven fusion power plants are considered a key technology on the road to climate neutrality. Highly reflective and thermally stable mirror systems are crucial for these fusion power plants in order to transport the laser light from the beam source to the tiny capsule of fusion fuel.

In the new SHARP research project, new types of high-performance mirrors are being developed for this purpose. The project is being funded with €8.4 million by the German Federal Ministry of Education and Research (BMBF).

The aim of the joint project SHARP (“Scalable Highpower Reflectors for Petawatts”) is to develop a new generation of highly reflective laser mirrors that meet the extreme requirements of future petawatt laser fusion reactors. To this end, large-area and internally cooled high-performance optical mirror systems are to be developed that have not yet been realized in this form.

“The SHARP project aims to lead to new manufacturing technologies that enable large-area mirrors with novel properties,” said Dr. Yakup Gönüllü from Schott. He is coordinating the new joint project, which officially began its three-year term with a kick-off event on March 4th.

“These high-performance mirrors represent an indispensable contribution to the realization of commercial laser fusion power plants in reliable continuous operation,” said Gönüllü. The research project has a total volume of €10.4 million, of which €8.4 million are being funded by BMBF as part of the “Basic technologies for fusion – on the way to a fusion power plant” initiative.

New technologies for continuous operation

Earlier work on laser mirror systems did not take the thermal aspect of laser radiation into account. In the future, however, the absorption-induced thermal energy input into the mirror systems will be crucial in the continuous operation of laser-driven fusion power plants.

In addition to the thermal stability of the new mirrors, the scalability of the technology is also a key factor in the project. Efficient production processes should contribute to the economic and ecological balance and thus to the commercialization of laser fusion power plants.

To achieve this goal, the SHARP consortium will develop the scientific and technical foundations for novel manufacturing technologies for superpolished, curved, large-area optics as well as methods for removing imperfect substrate areas and so-called “zero-defect” cleaning strategies.

“The challenge is that the laser mirrors have to withstand extreme loads over a long period of time,” said Dr. Nadja Felde, the project coordinator at Fraunhofer Institute for Applied Optics and Precision Engineering (IOF) in Jena, Germany. “The main aspect of this research project is therefore understanding and controlling the thermal properties of large-area mirror systems in design and production while maintaining reflectivity at the highest level.”

Prof. Dr. Thomas Höche from Fraunhofer Institute for Microstructure of Materials and Systems (IMWS) added, “Beyond laser fusion, the targeted developments have great potential for applications in other future markets, especially for high-power laser applications and laser material processing, but also in space communication and especially for the next generation of substrates and coatings for EUV lithography.”

The SHARP consortium is coordinated by Schott and brings together several companies and institutes in the field of optics, including Layertec, Asphericon, 3D-Micromac, OptiXfab, Cutting Edge Coatings, Robeko, Laser Zentrum Hannover, as well as the IOF and IMWS.