The Largest Private Laser Ever Built Has Been Activated, Aiming for One Thing Only
On Wednesday, Xcimer Energy activated Phoenix, the laser system that the Denver company claims is the largest ever owned by a private entity. This is the first engineering milestone for the company since its inception: a prototype designed to demonstrate that inertial confinement fusion can become a replicable industrial system, stepping outside the boundaries of a "laboratory experiment."
The facility, housed in a 74,000 square foot (approximately 6,900 square meters) building in Denver, rests on what Xcimer itself calls "unconventional" architecture: a krypton fluoride (KrF) laser combined with a stimulated Brillouin scattering (SBS) technique to compress a pulse lasting one microsecond into the nanosecond timeframe that fusion requires. The SBS optical core is 38 meters long, and the source operates at pulse energies exceeding 1 kilojoule: according to the company, this is the highest energy and the greatest spatial extent ever achieved by a device of this type.
Why Not Another NIF
The declared reference is the National Ignition Facility (NIF), the Lawrence Livermore National Laboratory's facility that, in December 2022, demonstrated for the first time a net energy gain from a fusion reaction, producing 8.6 megajoules of fusion energy from 2 megajoules of incoming laser light, as we have already reported. The NIF uses 192 solid-state laser beams focused on a target the size of a pencil eraser.
Xcimer starts from a precise premise: the purpose for which the NIF was created is scientific instrumentation. Its glass technology, the company argues, remains too costly, complex, and burdensome to maintain for generating electricity on a grid scale. Hence, the choice of krypton fluoride and an architecture with only two beam lines, compared to NIF's 192, designed for greater efficiency, lower thermal stress, and compatibility with industrial production.
The gain demonstrated at Livermore is a scientific balance, measured between the energy deposited on the target and the energy released: it does not take into account the hundreds of megajoules required to power the entire laser apparatus. The thesis of co-founder and president Alexander Valys is that "commercial laser fusion becomes possible only if the laser system itself becomes drastically simpler, cheaper, and manufacturable." Therefore, the game is played in the economic field, focused on the cost of the laser.
The Roadmap
Phoenix is the first step. Xcimer's plan includes Anvil (2028), a commercial-scale amplifier capable of delivering 200 kilojoules to the target; Vulcan (early 2030s), a system designed for 4-12 megajoules aimed at achieving energy balance at the outlet and for national security applications, with the site selection expected by the end of this year; and finally Athena (mid-2030s), the first fusion laser power plant intended for the continuous generation of electricity for the grid.
The company, supported by private investors and funds from the U.S. Department of Energy, is participating in the federally funded Milestone-Based Fusion Development program. Co-founder and CEO Conner Galloway framed Phoenix as an industrial operation even before a technological one: rebuilding expertise in high-energy excimer lasers that the U.S., he says, largely abandoned after the Cold War, recovering specialized supply chains and the last engineers with direct experience on these systems.
The gap between what Phoenix is today and what will be needed tomorrow is immense: just over 1 kilojoule versus the millions of joules of a power plant. Xcimer claims to have built the first piece of the architecture to bridge this gap. The next step will be the site selection for Vulcan, expected by the end of the year.