Direct visualization of the complete evolution of femtosecond laser-induced surface structural dynamics of metals

An ultrafast optical imaging technique has been used to thoroughly characterize the interaction between a femtosecond laser beam and a metal. While an impressive array of techniques have been used to explore what happens when a femtosecond laser beams interacts with a metal surface, none has succeeded in fully characterizing the process, and so many questions remain. Now, researchers at the University of Rochester in the USA led by Chunlei Guo have developed an optical imaging technique that analyzes scattered rather than reflected light. This technique allowed them to capture the complete laser-induced dynamics of a metal surface in both space and time. The imaging technique revealed that transient surface structures appear after about 100 picoseconds and that cooling and resolidification of molten metal occur two orders of magnitude slower than previously predicted.