Researchers have captured the strange behavior of laser induced gold

A new study conducted by the US Department of Energy's SLAC National Accelerator Laboratory has revealed the strange behavior of gold when impacted by high-energy laser pulses.

When certain materials are subjected to strong laser excitation, they will quickly disintegrate. But gold is exactly the opposite: it becomes more resilient and resilient. This is because the way gold atoms vibrate together - their phonon behavior - has changed.

"Our research findings challenge previous understanding, indicating that under certain conditions, metals like gold become stronger rather than melting when subjected to strong laser pulses," said Adrien Descamps, a researcher at Queen's University of Belfast who led the study during his graduate studies at Stanford University and SLAC. This is in stark contrast to semiconductors, which become unstable and melt.

For decades, simulations have hinted at the possibility of this phenomenon, known as phonon hardening. Now, using SLAC's linear accelerator coherent light source, researchers have finally brought this phonon hardening to people's attention. The team has published their research results in Scientific Progress.

"It's a fascinating journey to see our theoretical predictions validated in experiments," said collaborator Emma McBride, a researcher at Queen's University Belfast and former Panofsky researcher at SLAC's high-energy density science department. The accuracy of measuring these phenomena on LCLS is astonishing, opening up new possibilities for future research in materials science.

In their experiment, the team aimed an optical laser pulse at a thin gold film in an extreme conditions material laboratory chamber, and then used ultrafast X-ray pulses from LCLS to capture atomic level snapshots of material reactions. This high-resolution glimpse of the world of gold atoms allows researchers to observe subtle changes and capture the moment when phonon energy increases, providing specific evidence of phonon hardening.

"We use X-ray diffraction in LCLS to measure the structural response of gold to laser excitation," McBride said. This reveals insights into the arrangement and stability of atoms under extreme conditions.

Researchers have found that when gold absorbs extremely high-energy optical laser pulses, the force that holds its atoms together becomes stronger. This change causes atoms to vibrate faster, which can alter the reaction of gold to heat and may even affect its melting temperature.

"Looking ahead, we are pleased to apply these findings to more practical applications, such as laser processing and material manufacturing, where understanding these processes at the atomic level may lead to improvements in technology and materials," Descamps said. We also plan to conduct more experiments and hope to explore these phenomena on a wider range of materials. For our field, this is an exciting moment, and we look forward to seeing where these findings will take us.

Source: Laser Net