RTX backs Xcimer Energy, targeting fusion and air defence lasers
What's the deal? RTX VenturesDealroom has a profile for this one. Try Dealroom →, the venture arm of defence giant RTXDealroom has a profile for this one. Try Dealroom →, has taken a minority stake in laser fusion company Xcimer Energy in a late-stage round. The Denver-based startup develops scalable, multi-kilojoule-class pulsed-laser technology.
The two also signed a teaming agreement to explore integrating Xcimer's lasers into RTX's defence systems, aiming to give the US military new directed energy tools to counter airborne threats.
What's the endgame? Xcimer wants to build the "biggest, brightest, and most powerful lasers" for both commercial fusion and air defence. It expects to deliver fusion energy to the grid by the mid-2030s.
The company argues the core challenge is the same for both markets: a laser that fires repeatedly and reliably at low cost per joule, while being mass-manufacturable and energy efficient. RTX will pair that with its combat-proven defence expertise.
Why now? In June, the US Department of Energy approved Xcimer's fusion pilot power plant design under its Milestone-based Fusion Development Program. Xcimer received the largest laser fusion award from that program, positioning it as a frontrunner in commercialising laser fusion.
"As the United States accelerates the development of next-generation air defense, the need for affordable and scalable directed energy systems has never been more urgent," said Conner Galloway, Xcimer's co-founder and chief executive officer.
By the numbers: Xcimer has raised nearly $200M from investors including HedosophiaDealroom has a profile for this one. Try Dealroom →, Breakthrough Energy VenturesDealroom has a profile for this one. Try Dealroom →, Lowercarbon CapitalDealroom has a profile for this one. Try Dealroom →, Emerson Collective, and Prelude VenturesDealroom has a profile for this one. Try Dealroom →. RTX, its new backer, reported 2025 sales of more than $88 billion and employs over 180,000 people.
The signal: The deal ties clean energy ambitions to defence demand, letting one laser platform serve two markets. For Xcimer, a strategic investor with military reach could turn a long fusion timeline into nearer-term revenue.
Image credit: Generated with Gemini
