U-M's ZEUS laser, the strongest in the U.S., is about to get even more powerful

The ZEUS laser at the University of Michigan (U-M) is the strongest laser in the United States – and it's about to become even stronger, ushering in a new era of scientific research and development.

Currently operating at an electrical power output of two petawatts, this summer ZEUS’ output will soar to three petawatts thanks to a new lab-grown titanium-infused sapphire crystal from Salem, Mass. One of only a few of its size in the world, this crystal is larger, features more precise optics, and offers a level of refinement that surpasses the sapphires currently in use. Having spent the last four years being manufactured to ZEUS’ required specifications, it will arrive at U-M by August. 

John Nees is the head of laser construction and a research scientist in electrical and computer engineering at U-M. He breaks down what the most powerful laser in the United States does in layman’s terms.

"It can accelerate electrons, it can accelerate ions, and with the accelerated electrons and focusing light tightly, it can give us really high intensities," he says.

At its core, Nees says, operating the ZEUS laser involves "shooting high-power lasers at plasma physics" — but that’s only the tip of a vast and remarkable scientific iceberg. ZEUS’ upgrade will allow for research that will push the boundaries of particle acceleration, radiation generation, and nuclear fusion, with potential applications ranging from advanced cancer treatments to cleaner energy.

With the added petawatt of power, ZEUS will amplify its current capabilities — advancing research in cancer and disease treatment, enhancing X-ray and imaging technologies, and deepening our understanding of experimental physics. 

"The goal is to do fundamental research. And then if we can find something that really spins off well, like the really precise X-rays or compact ion acceleration or something new, maybe, we'll try to find ways to apply that and develop the technologies," Nees says. 

Supported by a Cooperative Agreement Grant from the National Science Foundation (NSF), the U-M research team meets monthly with NSF representatives to review ZEUS’ results, goals, and risk management strategies. This ongoing collaboration fosters an interactive environment that enables the ZEUS team to pursue a wide range of advanced research.

Like many research institutions across the country, U-M is facing federal funding cuts, but Nees and his team are prepared to keep working toward their goals.

"I think there is a feeling like it's going to be a little bit harder to do fundamental research that doesn't have a target towards a particular application," Nees says. "We're looking more towards adopting the goals of people that need to do research, which is targeted at making a product or getting some discovery out the door. We're pretty far from the product manufacturing side of things in terms of making an idea work. It takes time. Now we want to bring in a little bit more of the practical applications as much as we can."

U-M isn’t exploring these practical applications in isolation. Collaboration within the department is robust, and research groups from across the country frequently utilize the ZEUS lab to pursue their own research and development goals, supported by Nees and his team. 

"This technology that we have here, there might be some limitations in terms of putting it into practical use, but we also share what we're doing with other people that are pushing towards more practical solutions to laser technology," Nees says.

One potential real-world application of the ZEUS laser beyond the laboratory is in targeting and disrupting tumor growth within the body. Nees explains that ZEUS’ accelerated ions can be precisely calibrated to reach a medically predetermined treatment site within the body. 

"We are trying to get laser-based ion accelerators to the point where they can really produce reliable ion beams that can do damage at a particular depth that we can choose," he says.

With the arrival of the new sapphire crystal, assembly is expected to extend into the coming year. Nees anticipates beginning experiments at the three-petawatt scale in 2026. As the most powerful laser in the United States becomes even more formidable, the future of the ZEUS team looks bright.