What once sat dormant for nearly a decade—a powerful, highly specialized instrument known as a Free-Electron Laser (FEL) at the University of Hawaiʻi at Mānoa—is now sparking back to life, thanks to a new generation of accelerator physicists, determined to restore the FEL’s brilliance and redefine its potential.
Why the FEL matters
Unlike conventional lasers, the FEL produces tunable light (light that can be adjusted to different colors or energies) by accelerating electrons through alternating magnetic fields. This unique mechanism makes it a versatile tool, allowing researchers to probe matter at the molecular and atomic scale, making it a vital tool in physics and chemistry to biology and materials science. At UH Mānoa, the FEL facility engages in:
- Biological research
- Materials science research
- Nanostructure wake research
- Fundamental physics
- Advanced light source development
Since its invention, the FEL has enabled major breakthroughs in advancing scientific understanding, such as capturing ultrafast chemical reactions, determining the structure of complex proteins for drug development, and probing materials at the atomic scale to inform next-generation electronics and energy technologies.
Revival and expansion
In 2024, UH Mānoa took a strategic leap forward by hiring two rising stars in accelerator physics: Assistant Professor Siqi Li from the SLAC National Accelerator Laboratory, and Assistant Professor Niels Bidault from CERN, the European Organization for Nuclear Research in Switzerland. Their mission: restart the FEL, upgrade its capabilities and carve a new path forward.
“Operating the FEL is like building a Swiss watch, but at the scale of a particle beam.” — Niels Bidault
“Operating the FEL is like building a Swiss watch, but at the scale of a particle beam,” said Bidault. “It requires precision across every domain—electrical engineering, vacuum science, magnets, diagnostics, high-voltage systems. Everything must align within millimeters or less in order to work.”
Li and Bidault are working with a team of two postdocs and several undergraduate students on tech upgrades. In addition, Li is leading a nearly $1-million Department of Energy Established Program to Stimulate Competitive Research-funded project that develops a comprehensive simulation framework to fully understand FEL physics and combines traditional beam physics with cutting-edge machine learning techniques to optimize the FEL’s controls.
Related UH News stories:
- Renowned visiting accelerator expert praises UH Mānoa’s physics research innovations, February 24, 2025
- 3 UH research projects earn nearly $1M by Dept. of Energy, October 2, 2024
For more on how the FEL is helping to train the innovators of tomorrow, see Noelo’s 2025 cover story. Noelo is UH’s research magazine from the Office of the Vice President for Research and Innovation.
