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25 Jun 2025
World of Photonics delegates hear about the need to scale up laser diode and optics production for a potentially giant future market.
by Mike Hatcher in Munich
Commercial laser-based fusion energy plants could be rolled out at scale by 2040, if a host of challenges faced by manufacturers of laser diodes and large-scale optics can be met in the meantime.
That was the central message heard by LASER World of Photonics attendees during a series of industry presentations dedicated to the opportunities of the emerging fusion market.
NIF gain
Opening the session Constantin Häfner, who spent 15 years working at California’s National Ignition Facility (NIF) fusion demonstrator before becoming director of the Fraunhofer Institute for Laser Technology (ILT) in 2019, suggested that the the photonics industry was now on a path to “mass-scaling” laser and optics technology for future fusion demands.
He highlighted recent developments at NIF, where the December 2022 “fusion ignition” experimental breakthrough has now been followed up several times, with energy gain increasing rapidly.
Most recently the NIF team has demonstrated an energy output of 8.6 megajoules (MJ) from a laser input of 2.1 MJ, meaning that the “gain” figure has now risen from just over unity in the original demonstration to more than 4.
But while that progress - as well as some $9 billion of equity investment in fusion startups - suggests that the technology is on a path towards reality, Häfner pointed out that to be economically viable the gain figure would need to ramp up alongside dramatic improvements to the production scale and cost of key technologies on view this week at the World of Photonics trade show in Munich, Germany.
He showed calculations indicating that the cost of a future diode-pumped solid-state laser driver for fusion energy would be dominated by the thousands of diode emitters required, which would account for 60 per cent of the total, as well as large optics.
In principle these could be used to generate a 3 MJ system from 400 individual beams producing 7.5 kJ, at a repetition rate of 16 Hz - equivalent to an average laser power of 120 kW.
Producing the vast number of diodes and optics at the requisite price point remains a daunting challenge, but Häfner urged the photonics industry to take inspiration from the automotive sector and the presence of the Automatica trade show alongside LASER World of Photonics this year as a way to approach the necessary scale-up.
The investment required will be similarly huge, but the rewards on offer could, thinks Häfner, amount to a future annual market worth in excess of $100 billion just for the laser elements used in fusion plants. That figure would dwarf the current entire laser market of around $23 billion.
Meeting diode demand
Following Häfner, a series of presentations looked at those scale-up challenges in finer detail, with Thomas Thiemann, senior VP for energy transition technologies at Siemens, saying “we need you” to the assembled audience of photonics professionals.
Outlining that battery technologies and pumped hydro will not be able to provide the kind of grid stability demanded in an era becoming dominated by fluctuating renewable energy sources, Thiemann suggested that fusion is in fact in competition with small modular reactor (SMR) nuclear fission and hydrogen gas facilities when it comes to providing future electrical baseload.
He said that prototype fusion energy plants could appear by 2035, with a rollout of commercial facilities in 2040 - if those scale-up challenges can be met. Siemens has already inked a non-exclusive development deal with Munich-based Marvel Fusion to explore the possibilities of laser-powered energy, describing the technology as “interesting enough” for the energy giant to pursue seriously.
One major player in any such production scale-up could be ams Osram, already a top-tier producer of LED chips in enormous volumes. Ulrich Steegmüller, the firm’s CTO, said his key message was that the laser industry should learn from the LED sector’s earlier efforts to scale, with similar tools and processes needed to produce the necessary volumes on gallium arsenide wafers.
Under a pair of federally funded German development projects, ams Osram is working to increase the output power of its quasi-continuous-wave (QCW) laser bars to 1 kW at 940 nm and 800 W at 880 nm, at a wallplug efficiency of 70 per cent - up from today’s 500 W, 60 per cent efficiency benchmark.
Establishing a supply chain capable of delivering the thousands of wafer-starts per week needed to keep pace with anticipated laser fusion demand would be a critical challenge, particularly when it comes to the “massive” amount of gallium material needed, although, again, lessons could be learned from the LED industry’s recycling approach.
Meter-scale optics
Next up was Frank Nürnberg from optical glass provider Heraeus Covantics, who said he was encouraged by the small but necessary first steps now being taken by the industry.
He highlighted the challenge presented by an anticipated need for hundreds of tonnes of fused silica material from which laser fusion optics would be fabricated, as well as the long lead times typically required when ordering such material.
In an effort to shorten those lead times Heraeus has been working on new Ce-doped fused silica material under the ILT-led “PriFUSIO” project in Germany, with the first results on view at the Heraeus booth at this week’s trade show.
Turning that glass material into high-quality meter-scale laser optics is another fundamental challenge for the industry, and one being taken on by Jena-based Layertec. Rounding up the session company CEO Alexander Ancsin outlined the need to grind, polish, clean, coat, and measure such bulky components with high precision.
Ancsin explained that the coating element accounts for nearly one-third of the overall component cost currently, with raw material, metrology, and shaping requirements making up much of the remainder.
Critical challenges for this part of the fusion supply chain include streamlining production and automating metrology steps to reduce the need for manual inspection, with Ancsin echoing comments from the other presenters when he said that applications for such components in addition to laser fusion would be needed to ensure a viable future industry.
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