Ultrafast light-induced magnetization dynamics in ferromagnetic semiconductors

We develop a theory of the magnetization dynamics triggered by ultrafast optical excitation of ferromagnetic semiconductors. We describe the effects of the strong carrier spin relaxation on the nonlinear optical response by using the Lindblad semigroup method. We demonstrate magnetization control during femtosecond timescales via the interplay between circularly polarized optical excitation, hole-spin damping, polarization dephasing, and the Mn-hole spin interactions. Our results show a light-induced magnetization precession and relaxation for the duration of the optical pulse.