EN
Phase change random access memory devices made from chalcogenides compounds, such as Ge_{2}Sb_{2}Te_{5}, have attracted much attention because of their high-speed read-write and low power consumption capabilities. The phase change in Ge_{2}Sb_{2}Te_{5} is thought to be characterized by the displacement of Ge atoms, accompanying relaxation of surrounding Sb and Te atoms. Here we examine a new approach, that is the manipulation of Ge-Te bonds using linearly-polarized femtosecond near-infrared optical pulses. As a result, p-polarized pump pulses are found to be more effective in inducing the precursor of phase change, probably due to the atomic arrangements along the unique axis of the superlattice structure.