Physicists Predicts Novel Phenomena in Exotic Material

Physicists Predicts Novel Phenomena in Exotic Material

A SLAC-led research team manipulated a beam of electrons (from top left to bottom right) with conventional laser light (red) in a way that could produce purer, more stable pulses in X-ray lasers.

Credit: SLAC National Accelerator Laboratory

Researchers from the Department of Energy's SLAC National Accelerator Laboratory and Shanghai Jiao Tong University in China have developed a method that could open up new scientific avenues by making the light from powerful X-ray lasers much more stable and its color more pure.

The idea behind the technique is to "seed" X-ray lasers with regular lasers, whose light already has these qualities.

"X-ray lasers have very bright, very short pulses that are useful for all sorts of groundbreaking studies," says SLAC accelerator physicist Erik Hemsing, the lead author of a study published today in Nature Photonics. "But the process that generates those X-rays also makes them 'noisy' -- each pulse is a little bit different and contains a range of X-ray wavelengths, or colors -- so they can't be used for certain experiments. We've now demonstrated a technique that will allow the use of conventional lasers to make stable, single-wavelength X-rays that are exactly the same from one pulse to the next."

The method, called echo-enabled harmonic generation (EEHG), could enable new types of experiments, such as more detailed studies of electron motions in molecules.

"We need better control over X-ray pulses for such experiments," says Jerome Hastings, a researcher at SLAC's Linac Coherent Light Source (LCLS) X-ray laser, who was not involved in the study. "The new study demonstrates that EEHG is a very promising method to get us there, and it could become a driver for science that can't be done today." LCLS is a DOE Office of Science User Facility.