Rochester group funded to investigate developing ‘gamma ray laser’

31 Jul 2024

Federal money to allow U.S. and European collaboration to study coherent light sources beyond x-rays.

U.S. Federal funding will support scientists at the University of Rochester and their European collaborators to study the feasibility of coherent light sources beyond x-rays. Since the laser was invented in the 1960s, scientists have worked to increase lasers’ peak power and to design sources to produce coherent light at progressively shorter wavelengths that can improve image resolution and enable probing of quantum nuclear states.

Progress has been made with regard to peak power, most notably with the invention of chirped pulse amplification by Rochester researchers in the 1980s, a breakthrough that garnered the Nobel Prize in Physics in 2018. However, developing lasers that produce very high energy outputs, such as gamma rays, has remained elusive.

To overcome this obstacle, Rochester researchers secured National Science Foundation (NSF) funding in collaboration with colleagues from ELI Beamlines in the Czech Republic to investigate the coherence properties of the radiation emitted when dense bunches of electrons collide with a strong laser field. In doing so, the researchers aim to understand how to produce coherent gamma rays and use these new radiation sources for research and applications to create antimatter, study nuclear processes, and image dense objects or materials, such as scanning shipping containers.

“The ability to make coherent gamma rays would be a scientific revolution in creating new kinds of light sources, similar to how the discovery and development of visible light and x-ray sources changed our fundamental understanding of the atomic world,” said Antonino Di Piazza, a professor of physics at Rochester and a distinguished scientist at the university’s Laboratory for Laser Energetics, who is the lead investigator on the NSF grant.

US–Europe connections

The scientists will use complex theories and high-tech experiments to study how fast-moving electrons interact with the laser to emit high-energy light. They will start by looking at simpler cases, such as how one or two electrons emit light, before moving on to more complicated scenarios with many electrons, to produce coherent gamma rays. Such a result builds on the work of scientists who have created coherent x-rays, including the teams at SLAC National Accelerator Laboratory, European XFEL, and SACLA.

“We are not the first scientists who have tried creating gamma rays in this way,” said Di Piazza. “But we are doing so using a fully quantum theory—quantum electrodynamics—which is an advanced approach to addressing this problem.”

If successful, this project could lead to the creation of a gamma-ray free electron laser, a major goal in the scientific community, according to Di Piazza. “Of course,” he says, “step one is to show that the science is possible before building such a device.”

This work is also expected to contribute to advancing the science case for a potential future NSF OPAL high-power laser user facility at the University of Rochester, another NSF-funded project on which Di Piazza is a co-principal investigator, and which has the potential to be a unique open-access resource for the global scientific community.

NSF OPAL is part of NSF X-lites, an international network of networks studying extreme light in intensity, time, and space formed to address the grand challenge questions defined at the frontiers of laser-matter coherent interactions at the shortest distances, highest intensities, and fastest times.