Rapid phase change induced by double picosecond laser pulses and the dynamics of acoustic phonons

•The double pulse crystallization is easier than the single pulse crystallization.•The crystallization is a function of the intervals of double pump laser pulses.•The crystallization time decreases with the increase of the pump pulse intervals.•Acoustic phonons play a key role in the crystallization process.

For a given phase change material and composition, the double laser pulses better than a single pulse for the crystallization process. We investigated the crystallization process in Si15Sb85 thin films induced by double picosecond pulses with constant fluence and variable intervals. The crystallization degree is a function of the intervals of double pump laser pulses. The crystallization time decreased with the increasing of the intervals of the pump pulses. We believe that acoustic phonons play a key role in the crystallization process.