Ultrafast all-optical quantum control of magnetization dynamics

With the development of laser and magneto-optical technology and the discovery of a broad range of magnetic quantum materials exhibiting exotic properties and new physics, ultrafast magnetization dynamics has become increasingly appealing to advanced magnetic information technology. Furthermore, manipulating magnetization via light provides insights into interactions among multiple degrees of freedom in condensed matters and has revealed a wide range of nonequilibrium phenomena. In this minireview, we first present the theoretical considerations of ultrafast magnetization dynamics from both classical and ab initio points of view. We then discuss several aspects of state-of-the-art experimental studies on light-induced magnetization dynamics in various materials, including ultrafast demagnetization and magnetization reversal, as well as coherent-phonon-driven magnetization precession and phase transitions. In particular, we highlight the role of light-induced phonons from some recent work in the latter two aspects, providing a completely new perspective as well as an alternative approach for optical control of magnetization dynamics. As a powerful means of dynamical control and thanks to the progress and advances of experimental techniques, all-optical quantum manipulation of emergent materials is becoming one of the most far-reaching frontier research areas of ultrafast sciences.