Laser Fusion Startups Find New Partners in Defense Labs

Xcimer, a startup using lasers to pursue fusion power, has announced a partnership with RTX. RTX Ventures provided funding as part of the deal, and RTX can explore using Xcimer's lasers for its own work, according to TechCrunch. Fusion aims for net energy gain, producing more energy than is put in.

RTX is a conglomerate that includes defense contractor Raytheon. The agreement combines investment with access to high-energy laser hardware, which has uses beyond supplying electricity to the grid.

Pacific Fusion announced a memorandum of understanding with the National Nuclear Security Administration to work together on high-energy-density fusion experiments. High-energy-density physics is the study of matter under extreme heat and pressure. The same laser-matter interactions, diagnostic tools and target designs needed for energy gain are also used in stockpile stewardship science, the work of maintaining nuclear weapons without live testing.

Lasers are emerging as a distinct path within private fusion. Inertia Enterprises raised $450 million to develop a power plant using lasers, according to Bloomberg. Marvel Fusion GmbH, the German laser fusion startup, is exploring new uses for its laser technology including defense and medical applications, according to Bloomberg. Xcimer adds a third example. The companies differ, but all show dual applicability, meaning the same hardware can serve both energy and non-energy purposes.

Funding stays concentrated among a few companies. Proxima Fusion raised €411 million ($469 million) from a range of investors, with Google and RWE AG among the backers, according to Bloomberg. TechCrunch identifies Commonwealth Fusion Systems, Helion, TAE Technologies, Pacific Fusion, Proxima Fusion and Shine as fusion startups that have raised over $100 million. Fusion development requires heavy spending long before a plant sells its first electricity.

Public funding is moving in parallel. The U.S. Department of Energy released a finalized Fusion Science and Technology Roadmap to accelerate fusion development and commercialization, according to the Department of Energy. The Department also announced $134 million to advance U.S. fusion leadership, and awarded $128 million for the Fusion Innovative Research Engine (FIRE) collaboratives to seven teams, according to the Department of Energy.

Related tools and side bets are also in motion. Fusionality, founded by Google DeepMind alumni, builds control systems and simulation tools aimed at helping fusion startups accelerate development, according to TechCrunch. Think of it like tuning an engine while it runs. Avalanche Energy has a DARPA project focused on materials that convert damaging radiation into electricity, according to TechCrunch. Zap Energy, described as one of the better-funded fusion startups, undertook a partial pivot to add nuclear fission to its fusion work, according to TechCrunch. Fission, the splitting of atoms used in today's reactors, is distinct from fusion, the joining of atoms. Italy-based Enel partnered with Ansaldo to pursue small modular nuclear reactors, smaller factory-built fission plants.

The broader context here is procurement and test infrastructure. Private fusion firms need shots on target, pulsed-power facilities, radiation-hardened materials data and high-throughput simulation. Defense and NNSA laboratories already operate that infrastructure. Startups get experimental access and adjacent revenue that does not dilute ownership. Government partners get faster iteration on lasers, targets and controls.

In my view, the risk worth flagging is not simple mission drift. It is schedule and IP prioritization. Dual-use laser development can pull engineering time toward near-term deliverables with clear specifications and away from the longer physics and materials testing needed for a power plant. Contracts will need explicit boundaries around hardware access, data rights and publication of high-energy-density results.

Over the long arc, what this enables, if managed well, is still substantial. Better control software shortens experimental cycles. Radiation-to-electricity materials improve energy accounting in harsh neutron environments. Fission-adjacent work keeps teams funded while plasma performance matures. Defense partnerships do not solve confinement or net gain. They can fund the unglamorous layers around them.