The University of Michigan has achieved a monumental milestone in the realm of laser physics with the successful demonstration of the ZEUS laser facility reaching a peak power of 2 petawatts—doubling the power output of any other laser system currently operational in the United States. This unprecedented achievement marks not only a leap forward in the generation of ultra-intense light pulses but also heralds a new era for high-field science, as researchers begin to explore physical phenomena in regimes previously inaccessible to American laboratories. ZEUS, which stands for Zettawatt Equivalent Ultrashort laser pulse System, delivers laser pulses of extraordinary brightness and brevity, equivalent to more than one hundred times the total electrical power output of the entire globe, albeit concentrated into an ephemeral burst lasting a mere 25 quintillionths of a second.
Such staggering power levels are realized through a precisely engineered process in which an infrared laser pulse is first temporally stretched to prevent premature damage to limiting optical components. This pulse is then progressively amplified through multiple stages of pump lasers, intensively broadening both its spatial and temporal profile before compression back down to an incredibly thin disk-like pulse, approximately 8 microns thick and 12 inches in diameter. The laser is then focused to an astonishingly narrow spot less than a micron in diameter, thereby maximizing the intensity to levels where it can readily ionize air and create plasma. This manipulation of light underpins the unparalleled brilliance achieved by ZEUS and facilitates experiments that mimic conditions akin to those found in extreme astrophysical environments and beyond.
Director of the Gérard Mourou Center for Ultrafast Optical Science, Karl Krushelnick, highlights that this breakthrough ushers in a new chapter in American high-field science, enabling studies with profound implications across disciplines including medicine, materials science, national security, plasma physics, and quantum mechanics. The facility’s design as a user laboratory means it is accessible to national and international scientists, who submit proposals for experimental access based on rigorous scientific merit reviewed by an independent committee. This model ensures that ZEUS serves as a powerful catalyst for groundbreaking discoveries by tapping into a broad pool of expertise and creativity.
The first user-led experiments at 2 petawatts are spearheaded by Franklin Dollar, a professor of physics and astronomy at the University of California, Irvine. His team’s initials goal is to generate electron beams with energies rivaling those produced by particle accelerators spanning hundreds of meters. Achieving this within the compact confines of ZEUS’s vacuum chambers opens the gateway to laboratory-scale investigations of high-energy physics traditionally feasible only in large-scale accelerator facilities. The beam energies they target exceed what has been previously generated at ZEUS by a factor of five to ten, representing a transformative step forward in compact accelerator technology.
Anatoly Maksimchuk, a research scientist at U-M specializing in electrical and computer engineering, outlines the innovative approach underpinning these advancements. The method employs dual laser beams: one crafts a guiding plasma channel, while the other accelerates electrons within this channel through a process known as wakefield acceleration. Conceptually, the accelerated electrons “surf” akin to the wake behind a speedboat but at relativistic speeds. This effect is achieved by directing the ultra-intense laser pulse into an elongated and less dense gas cell filled with helium, which when ionized creates the plasma environment necessary to sustain electron acceleration along the extended path.
A crucial aspect of this approach is the interplay of plasma density and interaction length. Light travels slower through plasma than in a vacuum, allowing electrons to remain in the accelerating phase longer before overtaking the laser pulse. By designing the target gas cell to be longer and less dense, electrons gain prolonged acceleration time, enabling them to achieve higher energies. This flexibility in target design, coupled with the unparalleled laser intensity, allows ZEUS to push the boundaries of tabletop, plasma-based accelerators into previously unattainable energy regimes.
Looking toward the near future, the ZEUS team anticipates a signature experiment wherein these accelerated electrons collide head-on with incoming laser pulses of even greater power, projected to be 3 petawatts once the facility’s final sapphire crystal amplifier arrives later this year. In the frame of the electrons, this interaction will resemble a zettawatt-scale laser pulse—one thousand times stronger than the facility’s current peak power—offering a platform to probe physics at intensities hitherto impossible to achieve and opening doors to novel quantum and plasma phenomena.
The path to achieving this remarkable 2-petawatt milestone was neither straightforward nor swift. The acquisition and fabrication of critical components, notably the enormous titanium-doped sapphire crystal, represented significant engineering challenges. Measuring nearly seven inches in diameter, this crystal is central to amplifying the laser pulse to its full strength. According to ZEUS project manager Franko Bayer, manufacturing such crystals is a painstakingly slow process, requiring more than four years to complete, and only a handful of institutions worldwide possess the capability to produce them at this scale with the requisite optical quality.
Further technical hurdles included managing the complex degradation of diffraction gratings—key components responsible for stretching and compressing pulses—caused by carbon contamination within the vacuum environment. This unexpected darkening impaired the optical efficiency and risked damaging downstream optics. The team had to undertake extensive diagnostics to discern the cause, which ultimately was identified as deposits rather than permanent damage. This understanding allowed them to establish maintenance procedures balancing operational time with grating cleanliness, ensuring reliable and sustained high-power operation.
Despite these challenges, the ZEUS facility has efficiently transitioned from its previous phase, the HERCULES laser system, which operated at 300 terawatts, to delivering petawatt-level pulses. Since its grand opening in October 2023, ZEUS has hosted 11 separate experiments with participation from 58 researchers representing 22 institutions—including many international collaborators—underscoring its rapid integration within the global high-intensity laser research community. This vibrant experimental program is expected to accelerate as upgrades continue toward the ultimate 3-petawatt capability.
In terms of scale and operational agility, ZEUS occupies a footprint comparable to a school gymnasium, markedly smaller and more nimble compared to sprawling facilities like particle accelerators or the National Ignition Facility. John Nees, who leads the laser’s construction efforts, notes that this compactness allows for rapid iteration and openness to innovative scientific concepts, enabling ZEUS to attract a diverse spectrum of researchers and experimental designs. Such flexibility is essential for advancing frontier science in an evolving and competitive landscape.
Moreover, the research enabled at ZEUS holds significant promise for practical applications beyond fundamental science. According to Vyacheslav Lukin of the National Science Foundation Division of Physics, the unique capabilities of ZEUS can translate into advancements in medical imaging techniques, including enhanced soft tissue visualization, and improved modalities for cancer and other disease therapies. These translational opportunities highlight the broad societal impact that frontier laser science can wield, bridging laboratory discovery to tangible benefits for health and technology.
As the ZEUS laser facility continues to scale toward even greater power and experimental complexity, it stands poised to become a flagship in high-intensity laser research. Its innovative design, cutting-edge technology, and inclusive user program exemplify how collaborative efforts can rapidly expand the horizons of knowledge and technological prowess. Researchers and technologists alike eagerly anticipate new discoveries and advancements emerging from this powerhouse of light.
Subject of Research: High-power laser physics, plasma acceleration, ultrafast optics, and high-field science
Article Title: ZEUS Laser Facility at University of Michigan Achieves Unprecedented 2 Petawatts Power Level, Ushering in a New Era of High-Field Science
News Publication Date: 2024
Web References:
– https://ners.engin.umich.edu/people/krushelnick-karl/
– https://news.engin.umich.edu/2019/09/most-powerful-laser-in-the-us-to-be-built-at-michigan/
– https://faculty.sites.uci.edu/fdollar/lab-members/franklin-dollar/
– https://cuos.engin.umich.edu/researchgroups/hfs/profiles/anatoly-maksimchuk/
– https://cuos.engin.umich.edu/researchgroups/hfs/profiles/john-nees/
– https://eecs.engin.umich.edu/people/bayer-franko/
Keywords
High-power lasers, petawatt laser, ultrafast optics, plasma physics, wakefield acceleration, laser amplification, titanium-doped sapphire crystal, laser-driven electron accelerators, ultrashort laser pulses, applied physics, applied optics, laser systems
Tags: extreme light generationfuture of laser technologyhigh-field science advancementshigh-intensity light applicationslaser physics breakthroughslaser pulse amplification techniquesoptical component engineeringpetawatt laser technologyscientific research with lasersultrashort laser pulsesUniversity of Michigan laser researchZEUS laser facility
